Download 1 | Page TRUCK STOP Conceptually, think of momentum as “inertia

Momentum
The momentum of a single object is simply equal to the product of its mass and its velocity. The
symbol for momentum is “p”. Since mass is a scalar and velocity is a vector, momentum is also a
vector. The direction of momentum is always the same as that of the object’s velocity.
p = mv
Momentum is a vector so it has a magnitude and a velocity.
Its magnitude is the product of its mass and velocity, p = mv.
Its direction is the same as the direction of its velocity.
Units of Momentum
The unit of momentum can be derived from the above equation.
p = mv
The SI units of mass are kilograms (kg) and of velocity are meters / second (m/s). Therefore, the units
of momentum are kg· m/s.
There is no special name for the unit of momentum.
TRUCK STOP
Conceptually, think of momentum as “inertia in motion.” Newton’s first law explains that
objects in motion want to stay in motion. But just how much do moving objects wish to stay in
motion? Does a 1 kg skateboard moving at 10 m/s “want” to stay in motion as much as a 10,000
kg truck moving at the same speed? To answer, think about which one would be harder to stop.
Better yet, which one would you rather have approaching you?
1 kg
10,000 kg
1|Page
Practice Questions and Problems
Example 1: A 20 kg object has a velocity of 4.5 m/s in the positive x direction. What is its momentum?
p = mv
p = (20kg) (4.5 m/s)
p = 90 kg· m/s
p = 90 kg· m/s in the positive x direction
Example 2: A 60 kg object has a velocity of 1.5 m/s in the negative x direction. What is its momentum?
p = mv
p = (60kg) (-1.5 m/s)
= -90 kg· m/s
p = 90 kg· m/s in the negative x direction
Momentum of a Single Object
Classwork
1. What is the momentum of a 3000 kg truck traveling at 25 m/s?
2. A 1500 kg ferryboat has a momentum of 25000 kg∙m/s. What is the speed of the ferryboat?
3. A car travels at a constant speed of 24 m/s and has a momentum of 28800 kg∙m/s. What is the
mass of the car?
4. An 8 kg bowling ball rolls at a constant speed of 3 m/s. What is the momentum of the ball?
5. A bicyclist travels at a constant speed of 7 m/s. What is the total mass of the bicycle and the boy,
when the total momentum is 490 kg∙m/s?
6. When a 45 kg cannon ball leaves a barrel it has a momentum of 14000 kg∙m/s. What is the speed
of the ball at the end of the barrel?
Homework
7. A 45 kg woman runs at a speed of 5.6 m/s. What is her momentum?
8. A certain bowling ball rolls at a constant speed of 5 m/s. If the momentum of the ball is 42.5
kg∙m/s, what is its mass?
9. What is the speed of a 0.25 kg arrow with a momentum of 8 kgm/s?
10. A 1500 kg car travels 400 m in 12 s. What is its momentum?
11. An electron has a mass of 9.1x10
6
3.5x10 m/s?
-31
kg. What is its momentum if it is travelling at a speed of
12. A 3 kg stone is dropped from a height of 4 m. What is its momentum as it strikes the ground?
2|Page
Momentum of a Closed System of Objects
To determine the momentum of a system that has more than one object you have to add together the momenta of all
the individual objects.
psystem = p1 + p2 + p3 +…
psystem = m1v1 + m2v2 + m3v3 + …
Or
psystem = Σp
psystem = Σmv
So if a system were comprised of the objects in Example 1 and 2, above, then the momentum of that total system
would simply be the sum of those two momenta.
_____________________________________________________________________
Example 3: Determine the momentum of a system that consists of the two objects from Example 1 and 2, above.
psystem = Σp
psystem = p1 + p2
psystem = (90 kg· m/s) + (-90 kg· m/s)
psystem = 0
Sample Problems
Determine the momentum of a system that consists of two objects. If the speed of cart A is 0.33 meter per second
after the spring is released, what is the approximate speed of cart B after the spring is released?
A 1.2-kilogram block and a 1.8-kilogram block are initially at rest on a frictionless, horizontal surface. When a
compressed spring between the blocks is released, the 1.8-kilogram block moves to the right at 2.0 meters per
second, as shown.
What is the speed of the 1.2-kilogram block after the spring is released?
Example 4: Determine the momentum of a system that consists of the two objects. One object, m1, has a mass of 2
kg and a velocity of +5 m/s and the second object, m2, has a mass of 20 kg and a velocity of +3 m/s.
psystem = Σp
psystem = p1 + p2
psystem = m1v1 + m2v2
psystem = (2 kg) (+5 m/s) + (20 kg)(+3 m/s)
psystem = (10 kg· m/s) + (60 kg· m/s)
psystem = 70 kg· m/s
psystem = 70 kg· m/s in the positive x direction
______________________________________________________________________
3|Page
Example 5: Determine the momentum of a system that consists of the two objects. One object, m1, has a mass of 4
kg and a velocity of 17 m/s in the positive direction and the second object, m2, has a mass of 70 kg and a velocity of
4 m/s in the positive direction.
psystem = Σp
psystem = p1 + p2
psystem = m1v1 + m2v2
psystem = (4 kg) (17 m/s) + (70 kg)(4 m/s)
psystem = (68 kg· m/s) + (280 kg· m/s)
psystem = 348 kg· m/s
psystem = 348 kg· m/s in the positive x direction
The diagram below shows a 4.0-kilogram cart moving in the positive direction and a 6.0-kilogram cart moving in
the negative direction on a horizontal frictionless surface.
When the two carts collide they lock together. The magnitude of the total momentum of the two-cart system after
the collision is
Momentum of a System of Objects
Class Work
13. Determine the momentum of a system that consists of two objects. One object, m1, has a mass of
6 kg and a velocity of 13 m/s towards the east and a second object, m 2, has a mass of 14 kg and
a velocity of 7 m/s in that same direction.
14. Determine the momentum of a system that consists of two objects. One object, m1, has a mass of
6 kg and a velocity of 13 m/s in the direction of the positive x-axis and a second object, m2, has a
mass of 14 kg and a velocity 7 m/s in the direction of the negative x-axis.
15. Determine the momentum of a system that consists of three objects. One object, m 1, has a mass
of 7 kg and a velocity 23 m/s towards the north, a second object, m 2, has a mass of 9 kg and a
velocity 7 m/s towards the north and the third object, m3 has a mass of 5 kg and a velocity of 42
m/s towards the south .
Homework
16. Determine the momentum of a system of the two objects. One object, m 1, has a mass of 35 kg
and a velocity of 3.7 m/s towards the east and the second object, m2, has a mass of 57 kg and a
velocity of 4.3 m/s towards the west.
17. Determine the momentum of a system of the two objects. One object, m 1, has a mass of 35 kg
and a velocity of 3.7 m/s towards the north and the second object, m 2, has a mass of 57 kg and a
velocity of 4.3 m/s towards the south.
18. Determine the momentum of a system that consists of three objects. One object, m 1, has a mass
of 12 kg and a velocity 120 m/s towards the east, a second object, m 2, has a mass of 25 kg and a
velocity 18 m/s towards the west and the third object, m3 has a mass of 1 kg and a velocity of 350
m/s towards the east.
4|Page
Activity: How does a collision affect the motion of marbles?
Procedure:
1. Place 5 marbles, all identical in size and shape, in the center
groove of a ruler. Launch a sixth marble toward the five stationary
marbles. Note any changes in the marbles’ motion.
2. Now launch two marbles at four stationary marbles. Then launch
three marbles at three stationary marbles, and so on. Note any
changes in the marbles’ motion.
3. Remove all but two marbles from the groove. Roll these two
marbles towards each other with equal speeds. Note any changes in
the marbles’ motion.
Number of marbles
on the ruler
5 stationary
4 stationary
3 stationary
2 stationary
1 stationary
0 stationary
Number of marbles Observations
launched
1 launched
2 launched
3 launched
4 launched
5 launched
2 launched towards
each other
Questions:
1. How did the approximate speed of the marbles before each
collision compare to after each collision?
2. What factors determine how the speed of the marbles changes in a
collision?
3. What do you think would happen if three marbles rolling to the
right and two marbles rolling to the left with the same speed were
to collide?
5|Page
Collisions
• Elastic
• When an elastic collision occurs, objects bounce off each other with no loss in the total
kinetic energy of the system. The collision between billiard balls is very close to a
perfectly elastic collision.
m1v1i + m2v2i = m1v1f + m2v2f
•
•
Inelastic
In an inelastic collision objects change shape or stick together. (An egg dropped on the
floor)
m1v1 + m2v2 = (m1 + m2)vf
In an elastic collision the objects have different velocities before and after the collision.
Perfectly inelastic collisions will have different starting velocities but the same final velocity,
as they are stuck together and moving as one object.
All momentum problems use the same equation: Σpi = Σpf which translates into:
1. Elastic Collisions:
m1v1 + m2v2 = m1v1f + m2v2f
2. Inelastic Collisions:
m1 v1 + m2 v2 = (m1 + m2 ) vf
m1 = mass of 1st object
m2 = mass of 2nd object
v1 = velocity of 1st object
v2 = velocity of 2nd object
vf = final velocity of both objects
v1f = final velocity of 1st object
v2f = final velocity of 2nd object
6|Page
To solve momentum problems, always organize your information first. The best thing to do is to
draw a sketch, and label the masses and velocities. Then, determine whether the collision is
inelastic or elastic.
Example: A 13,500 kg railroad freight car travels on a level track at a speed of 4.5 m/s. It collides and
couples with a 25,000 kg second car, initially at rest and with brakes released. What is the speed of the
two cars after collision?
Step 1: Draw a sketch and label the masses and velocities.
Step 2: Determine whether the collision is inelastic or elastic.
The problem states the two freight cars couple or stick together which would make it an inelastic
collision thus: m1 v1 + m2 v2 = (m1 + m2 ) vf
Conservation of Momentum and Perfectly Inelastic Collisions
Classwork
19. *A 13,500 kg railroad freight car travels on a level track at a speed of 4.5 m/s. It collides and
couples with a 25,000 kg second car, initially at rest and with brakes released. What is the speed
of the two cars after collision?
20. *A 40 kg girl skates at 3.5 m/s on ice toward her 65 kg friend who is standing still, with open arms.
As they collide and hold each other, what is the speed of the couple?
21. *A 50 kg boy jumps off the front of a 1.5 kg skateboard moving forward. Find the skateboard’s
velocity immediately after the boy jumps, assuming that the skateboard’s initial velocity is 3.5 m/s
and the boy’s velocity when jumping off the front is 5 m/s.
22. *A 0.01 kg bullet has a speed of 700 m/s before it strikes a 0.95 kg wooden block that is
stationary on a horizontal frictionless surface and remains inside of it. What is the speed of the
block after the bullet becomes embedded in it?
23. *A cannon ball with a mass of 100 kg flies in horizontal direction with a speed of 600 m/s and
strikes a railroad freight car filled with sand and initially at rest. The total mass of the car and sand
is 25,600 kg. Find the speed of the car after the ball becomes embedded it the sand.
24. *A 0.01 kg bullet is fired at a 0.5 kg block initially at rest. The bullet, moving with an initial speed
of 400 m/s, emerges from the block with a speed of 300 m/s. What is the speed of the block after
the collision?
25. *A 50 kg boy jumps off the back of a 1.5 kg skateboard moving forward. Find the skateboard’s
velocity immediately after the boy jumps, assuming that the skateboard’s initial velocity is 3.5 m/s
and the boy’s velocity when jumping off the back is 5 m/s.
Homework
26. *Two football players with mass 85 kg and 110 kg run directly toward each other with speeds 4
m/s and 7 m/s respectively. If they grab each other as they collide, what is the combined speed of
the players just after the collision?
27. *An air track car with a mass of 0.55 kg and velocity of 5.8 m/s to the right collides and couples
with a 0.45 kg car moving to the left with a velocity of 3.9 m/s. What is the combined velocity of
the cars just after the collision?
7|Page
28. *An air track car with a mass of 0.25 kg and velocity of 3.4 m/s to the right collides and couples
with a 0.45 kg car moving to the left with a velocity of 3.9 m/s. What is the combined velocity of
the cars just after the collision?
29. *A 15000 kg railroad car travels on a horizontal track with a constant speed of 12 m/s. A 6000 kg
load is dropped onto the car. What will be the car’s speed?
30. *A 55 kg skater at rest on a frictionless rink throws a 3 kg ball, giving the ball a velocity of 8 m/s.
What is the velocity of the skater immediately after?
31. *A 0.015 kg bullet is fired at a 1.5 kg block initially at rest. The bullet, moving with an initial speed
of 500 m/s, emerges from the block with a speed of 400 m/s. What is the speed of the block after
the collision?
32. *A 40 kg surfer jumps off the front of a 20 kg surfboard moving forward. Find the surfboard’s
velocity immediately after the girl jumps, assuming that the surfboard’s initial velocity is 8 m/s and
the girl’s velocity when jumping off the front is 3 m/s.
33. *A 40 kg surfer jumps off the back of a 20 kg surfboard moving forward. Find the surfboard’s
velocity immediately after the girl jumps, assuming that the surfboard’s initial velocity is 8 m/s and
the girl’s velocity when jumping off the back is 3 m/s.
Elastic Collision Problems (with masses)
Classwork
34. *A ball of mass 0.34 kg moving with a speed of 2.7 m/s to the right collides head on with a 0.24
kg ball at rest. If the collision is elastic, what is the speed and direction of each ball after the
collision?
35. *An ice puck of mass 0.54 kg moving with a speed of 5m/s to the right collides with a 0.28 kg
piece of ice moving with a speed of 4.2 m/s to the right. If the collision is elastic, what is the speed
and direction of each ball after the collision?
36. *An air track car with a mass of 0.75 kg and velocity of 8.5 m/s to the right collides elastically with
a 0.65 kg car moving to the left with a velocity of 7.2 m/s. If the collision is elastic, what is the
speed and direction of each ball after the collision?
Homework
37. *An air track car with a mass of 0.85 kg and velocity of 3.4 m/s to the right collides elastically with
a 0.95 kg car moving to the left with a velocity of 4.9 m/s. If the collision is elastic, what is the
speed and direction of each ball after the collision?
38. *A ball of mass 6.5 kg moving with a speed of 15 m/s to the right collides head-on with a 3.5 kg
ball which is at rest. If the collision is elastic, what is the speed and direction of each ball after the
collision?
39. *An ice puck of mass 7.5 kg moving with a speed of 18 m/s to the right collides with a 2.5 kg
piece of ice moving with a speed of 4.2 m/s to the right. If the collision is elastic, what is the speed
and direction of each mass after the collision?
8|Page
Notes: Impulse
What does Newton’s Second Law have to do with momentum?
An object with __________ can be stopped if a __________ is applied against it for a given
amount of time.
A __________ acting for a given amount of time will change an object's momentum. Put
another way, an unbalanced force always accelerates an object - either speeding it up or slowing
it down. If the force acts opposite the object's motion, it slows the object down. If a force acts in
the same direction as the object's motion, then the force speeds the object up. Either way, a force
will change the velocity of an object. And if the velocity of the object is changed, then the
momentum of the object is changed.
In a collision, an object experiences a force for a specific amount of time which results in a
change in momentum. The result of the force acting for the given amount of time is that the
object's mass either speeds up or slows down (or changes direction). The impulse experienced by
the object equals the change in momentum of the object.
What is the impulse-momentum change equation?
9|Page
Change of Momentum and Impulse
Classwork
40. *A 1200 kg car accelerates from 13 m/s to 17 m/s. Find the change in momentum of the car.
41. *A small object with a momentum of 6 kg∙m/s to the west approaches head-on a large object at
rest. The small object bounces straight back with a momentum of 5 kg∙m/s. What is the change in
the momentum of the small object? What is the impulse exerted on the small ball? What is the
impulse exerted on the large object?
42. *A 0.03 kg golf ball is hit off the tee at a speed of 34 m/s. The golf club was in contact with the ball
for 0.003 s. What is the average force on ball by the golf club?
43. *A toy rocket achieves a velocity of 55 m/s after 3 s, when fired straight up. If the average force
exerted by the engine is 28 N, what is the toy’s mass?
44. *A 15000 kg air jet accelerates from rest to 45 m/s before it takes off. What is the change in
momentum of the jet?
45. *A 0.025 kg piece of clay is thrown into a wall and has a speed of 9 m/s before it strikes the wall.
Find the change in momentum of the clay and the impulse exerted on the clay if it does not
bounce from the wall.
46. *A small bouncy ball with a momentum of 8 kg∙m/s to the left approaches head-on a large door at
rest. The ball bounces straight back with a momentum of 6 kg∙m/s. What is the change in the
momentum of the ball? What is the impulse exerted on the ball? What is the impulse exerted on
the door?
47. *A 0.07 kg tennis ball leaves a racket with a speed of 56 m/s. If the ball is in contact with the
racket for 0.04 s, what is the average force on the ball by the racket?
48. *A 0.145 kg baseball reaches a speed of 36 m/s when a bat strikes. If the average force of 500 N
was applied on the ball by the bat, what is the impact time?
Homework
49. *A 0.17 kg hockey puck slows down from 54 m/s to 35 m/s when it slides on horizontal ice
surface. Find the change in momentum of the puck?
50. *A 0.01 kg bullet is fired at 250 m/s into a wooden block that is fixed. The bullet emerges from the
block with a speed of 120 m/s. What is the change in momentum of the bullet?
51. *A 0.05 kg tennis ball moves at a speed of 10 m/s and is struck by a racket causing it to rebound
in the opposite direction at a speed 16 m/s. What is the change in momentum of the ball? What is
the impulse exerted on the ball? What is the impulse exerted on the racket?
52. *A 0.25 kg beach ball rolling at a speed of 7 m/s collides with a heavy exercise ball at rest. The
beach ball bounces straight back with a speed of 4 m/s. That is the change in momentum of the
beach ball? What is the impulse exerted on the beach ball? What is the impulse exerted on the
exercise ball?
53. *A 0.16 kg hockey puck is moving on an icy horizontal surface with a speed of 5 m/s. A player
strikes the puck by a hockey stick, after the impact the puck moves in opposite direction with a
speed of 9 m/s. If the puck was in contact with the stick for 0.005 s, what is the average force on
the puck by the stick?
54. *A constant force of 12 N acts for 5 s on a 5 kg object. What is the change in object’s velocity?
10 | P a g e
55. *A small object with a mass of 1 kg moves in a circular path with a constant speed of 5 m/s. What
is the change in momentum during ½ of period; one period?
The diagram to the right depicts the before- and after-collision speeds of a car that undergoes a
head-on-collision with a wall. In Case A, the car bounces off the wall. In Case B, the car
crumples up and sticks to the wall.
a. In which case (A or B) is the change in velocity the greatest? Explain.
b. In which case (A or B) is the change in momentum the greatest? Explain.
c. In which case (A or B) is the impulse the greatest? Explain.
11 | P a g e
1) 75,000 kgm/s
2) 16.7 m/s
3) 1200 kg
4) 24 kgm/s
5) 70 kg
6) 311 m/s
7) 252 kgm/s
8) 8.5 kg
9) 32 m/s
10) 50,000 kgm/s
-24
11) 3.185x10 kgm/s
12) 26.6 kgm/s
13) 176 kgm/s
14) -20 kgm/s
15) 14 kgm/s
16) -115.6 kgm/s
17) -115.6 kgm/s
18) 1340 kgm/s
19) 1.58 m/s
20) 1.33 m/s
21) -46.5 m/s
22) 7.29 m/s
23) 2.33 m/s
24) 2 m/s
25) 286.83 m/s
26) -2.2 m/s
27) 1.435 m/s
28) -1.29 m/s
29) 8.57 m/s
30) -.44 m/s
31) 1 m/s
32) 18 m/s
33) 30 m/s
34) V1f = .46 m/s
V2f = 3.16 m/s
35) V1f = 4.454 m/s
V2f = 5.253 m/s
36) V1f = -6.07 m/s
V2f = 6.2475 m/s
37) V1f = -5.36 m/s
V2f = 2.791 m/s
38) V1f = 4.5 m/s
V2f = 19.5 m/s
39) V1f = -11.1 m/s
V2f = 24.9 m/s
40) ∆p=4800 kgm/s
55) ∆p1/2 period = -10 kgm/s
∆p1 period = 0
41) ∆psmall = 11 kgm/s
Ismall = 11 kgm/s
Ilarge = -11 kgm/s
42) 340 N
43) 1.527 kg
44) 675,000 kgm/s
45) ∆p = -.225 kgm/s
∆I = -.225 kgm/s
46) ∆p = 14 kgm/s
IB = 14 kgm/s
Idoor = -14 kgm/s
47) 98 N
48) .01044 s
49) -3.23 kgm/s
50) -1.3 kgm/s
51) ∆p = -1.3 kgm/s
Iball = -1.3 kgm/s
Iracket = 1.3 kgm/s
52) ∆p = -2.75 kgm/s
IBB = -2.75kgm/s
IEB = 2.75kgm/s
53) -448 N
54) 12 m/s
12 | P a g e
Lab: Balloon Toss
Physics
Research Question
What variables affect the impact force in a collision and in what manner do they affect the force?
Hypothesis
What effect will mass and collision time have on the impact force of a balloon in a collision
(when it strikes the ground)?
Procedure
The objective is to catch a thrown balloon without letting it break. The balloon successfully
caught after traveling the greatest distance wins a Homework pass.
Rules
The competition must be carried out in a safe and fair manner at all times!
1. Follow the written and spoken instructions of the referee (teacher) at all times. Failure to
do so is grounds for disqualification.
2. Each team shall have a thrower, a catcher, and a courier
3. The thrower is in charge of throwing the balloon to the catcher. The thrower must keep
his/her throws within the team's throwing lane (as specified by the referee). Throwing
outside the lane disqualifies the team. The thrower must throw the balloon with his/her
bare hands.
a. The catcher must wear the safety goggles and the garbage bag poncho (see
construction instructions below) during competition. The catcher is responsible for
catching the balloon without breaking it. The catcher must catch the balloon with
his/her bare hands.
b. The courier carries the caught balloon from the catcher to the thrower after a
successful catch.
4. The details of the throwing and distance requirements will be announced by the referee
on the field of competition. Be sure to listen carefully!
5. If the team's balloon is broken, the team is responsible for cleaning up the mess as
thoroughly as possible. It is important that we leave the field of competition as we found
it, not littered with broken balloons! The garbage bag poncho is a good temporary
receptacle for broken balloon parts.
6. No member of any team can help or hinder the performance of any other team.
7. Violation of any of the written or spoken rules or instructions is grounds for
disqualification.
13 | P a g e
Pregame Instructions
1. Alignment. Throwers form a line standing side-by-side. Use shadows for alignment:
each thrower stands in the shadow of his/her neighbor nearer the sun. Each thrower can
stand with his/her arms stretched out to the side and not touch the outstretched arms of
his/her neighbor.
2. Tosses. All tosses are launched on the instructor's/referee's signal.
3. Legal catches. A catcher must catch the balloon with his or her bare hands. The catch
must be made at or beyond the distance in play.
4. Penalties. Three strikes and you're out.
a. Broken balloon = disqualification (three strikes)
b. Balloon hits ground and doesn’t break = one strike + repeat at that distance (do
over)
c. Balloon falls short (catcher must move closer to thrower to make the catch) = two
strikes + do over
5. Rounds. After each toss and catch, catchers move back three giant steps and catch from
there.
Post-Game Analysis
1. What was the strategy for catching a long-range, thrown balloon? Answer using words
and pictures.
2. What's the physics that explains the success of this approach?
3. Use the principle described in your answer to discuss why a raw egg could not be used in
competitive baseball.
4. Assume that we were able to collect the following table of data for a balloon toss lab.
The table represents numerical values for force, time, mass, velocity change, impulse,
and momentum change for various catches of a balloon. Use the table to answer the
following questions.
Mass
∆Velocity ∆Momentum Impulse
Force
∆Time
(kg)
(m/s)
(kg m/s)
(N s)
(N)
(s)
a.
0.50
-4.0
0.010
b.
0.50
c.
0.10
d.
0.20
e.
0.50
f.
0.50
-2.0
0.100
-0.40
-8.0
0.010
-80
-400
-8.0
1.0
0.010
5. Use the laws of physics in this lab to explain why bungee jumpers use a stretchy cord
instead of a steel cable.
6. How do your findings explain the purpose of airbags in cars? Refrain from using words
like “cushion” or “absorb.” Do use words like “stopping time,” “stopping force,” or
“changes in momentum.
14 | P a g e
Rubric – Balloon Toss
Heading
(1 pt.)
Research Question
(2 pts.)
Hypothesis
(5 points)
Sketch & Description
(2 pts.)
Post Game Analysis
(10 pts.)
Total =
Student labels the date in the
upper left hand corner and title
of lab in all CAPS in lab
notebook.
Student states the research
question of the lab as a
statement.
Student states hypothesis and
explains their prediction.
Student sketches materials
used in lab and a brief
description of what they did.
Student answers analysis
questions accurately and in
complete sentences.
/20 points
15 | P a g e
Egg Drop
Honors Physics
WHO WILL BUILD THE LIGHTEST PROJECT AND STILL
SURVIVE?
Objective
You are to make or build something that is the lightest possible weight, and yet durable enough
to protect an egg dropped from a high vantage point, so that the egg doesn't break from the fall.
Think of the egg as a passenger in a car going through a crash test. Your job is to design a
contraption that will result in the egg decelerating slowly.
Date Assigned:
DATE DUE:
Rules
1. Of course the egg and its contraption must hit the ground! The egg will be dropped from
the football stands in a succession of different heights. We will be going outside so please
dress appropriately!
2. You may work by yourself or with one other person in your class period.
3. Materials:
a) No balloons or parachutes are allowed.
b) You may not use Nerf® balls, pillows, tempurpedic foam, textile stuffing or
stuffed animals to protect your egg. Some ideas of items used in the past: cotton,
Styrofoam, rubber bands, straws, ziplock bags and toilet paper.
c) I will provide raw, store bought large chicken eggs for the competition. You must
do the final assembly by inserting my egg into your contraption during the short
time allotted in class before testing begins.
4. Limitations:
a) The project must weigh less than 200 grams. You may bring in your project early
to weigh it - if your project is overweight you may take it home and make any
necessary alterations. If you wait until the last minute and your project is
overweight, it will be disqualified.
b) Your egg project must fit on a regular size sheet of paper. (Note that it may be 3 ft
high and still fit on the paper.)
c) Your egg project must have an opening the size of my pinky finger where I can
see a portion of the egg.
5. Your project must have a name, eg. Dumbo.
6. Once your design has hit the ground it will be your responsibility to retrieve your egg and
show it to me for scoring.
7. This is a competition! Your grade will be dependent on how everyone else does.
16 | P a g e
Name: _____________________________________
Date: ___________
Name of Project: ________________________________________
Scoring for Egg Drop Contest
All materials used are within regulations.
no)
yes/no
(disqualified if
80 points are awarded if project is built according to the rules.
Mass of contraption:
________
(disqualified if greater than 200 g)
1-10 points will be granted on the mass of the contraption. Lightest will receive 10 points,
heaviest=1.
0 1 2 3 4 5 6 7 8 9 10
Points are awarded based on the survival of your egg.
10 – Egg survives the fall fully intact
7.5 – Egg is cracked, but intact
5 – Egg is broken (any white or dampness coming out of shell)
0 – Egg is destroyed (smashed to bits, yolk oozing out, etc.)
TOTAL POINTS EARNED: _______________
Grade: _________ A
B
C
D
F
17 | P a g e
Conservation of Momentum
Honors Physics
Overview: Design and conduct an experiment to answer the question below. Collect data and
prepare a formal lab report detailing your investigation.
The Question: When a projectile strikes a stationary target, will the target move more if the
projectile sticks to the target, or if the projectile bounces off of the target?
To do:
1. Plan your experiment and develop your hypothesis. Think about the materials and
measurement tools that you will use, and plan your procedure.
2. Conduct your experiment and collect data.
3. Prepare a formal lab report. This must be completed in your lab books. You may
share data with your lab partners, but you must prepare your own lab report. It
must include all of the sections below.
Lab Report Sections:
1. Title
2. Research Question
3. Hypothesis
4. Materials
5. Procedure (steps followed)
6. Data Display (table, graph, etc.)
7. Data Analysis
18 | P a g e
Conservation of Momentum
Honors Physics
Research Question
After reading the lab, create your own research question and make a prediction in response to the
question you create.
Pre-Lab Discussion
This experiment demonstrates the conservation of momentum during an explosion. This is
accomplished by calculating the momentum of two carts pushing away from each other. When
two carts push away from each other and no net force exists, the total momentum of both cars is
conserved. Because the system is initially at rest, the final momentum of the two carts must be
equal in magnitude and opposite in direction so the resulting total momentum of the system is
still ZERO.
Materials
2 carts
Motion Sensors
Mass Bars
Digital Balance
Dynamics track
String
Procedure
1. Measure the mass of the empty red and blue carts. Record in Table 1. Remember to convert
from grams to kilograms (divide by 1000).
2. Level the track by setting a cart on the track to see which way it rolls. Adjust the leveling feet
to raise or lower the ends until a cart placed at rest on the track will not move.
3. Add a motion sensor to each side of the track and plug them into the computer. In the class
folder, open the DataStudio file: conservation_of_momentum.ds.
4. Place the two carts against each other with the plunger of one of the carts pushed completely
in and latched in its maximum position, and the other facing the opposite direction. Tie the
string between the carts.
5. To make sure neither sensor is hit by the carts, start the carts closer to the end of the side with
the heavier mass.
6. Press start in DataStudio and push the plunger release button with a mass bar. Watch the two
carts move until the string snaps them back. If either cart reaches the motion sensor, change
the starting point of the carts and repeat this step. Look at the velocity vs. time graph for
each cart and record the highest speed value in Table 1 (it should be negative in DataStudio,
but write the absolute value).
7. Repeat steps 4 and 5 by adding or removing mass according to Table 1. Before starting a
new run, select “Delete Last Data Run” under the “Experiment” menu.
19 | P a g e
Data Table 1
Mass of empty Blue Cart = ___________ kg
Trial
Blue Cart Mass
Added
Total
Mass
Mass
(kg)
(kg)
Red Cart Mass
Added
Total
Mass
Mass
(kg)
(kg)
1
0
0
2
0.250
0
3
0.500
0
4
0.750
0
5
1.000
0
6
0.750
0.250
7
0.500
0.250
8
0.250
0.500
9
0
0.500
10
0
0.750
Mass of empty Red Cart = ___________ kg
Table 1
Velocity
Blue
Red
Cart
Cart
(m/s)
(m/s)
Momentumexperimental
Blue Cart
(kg · m/s)
Red Cart
(kg · m/s)
Difference
(kg · m/s)
Calculations (Provide one sample calculation for each)
1. Calculate the experimental momentum of each cart, using the formula: p = mv.
2. Subtract the momentum of the red cart from the blue cart. Put in the last column above.
Questions
1.
2.
3.
4.
Is momentum conserved in this experiment? Explain, using actual data from the lab.
When carts of unequal masses push away from each other, which cart has a higher velocity? Explain.
When carts of unequal masses push away from each other, which cart has more momentum? Explain.
Did all of your results show conservation of momentum? Describe 3 possible sources of error and
explain specifically how they might have changed the results.
20 | P a g e
Rubric – Conservation of Momentum
Honors Physics
Heading
(1 pt.)
Research Question
(2 pts.)
Hypothesis
(4 points)
Sketch & Description
(1 pt.)
Data Table & Graphs
(5 pts.)
Analysis
(12 pts.)
Total =
Student labels the date in the
upper left hand corner and title of
lab in all CAPS in lab notebook.
Student states the research
question of the lab as a question
or statement.
Student states hypothesis and
explains their prediction.
Student sketches materials used in
lab and a brief description of what
they did.
Student uses Microsoft
Word/Excel or similar program
to create a data table.
Student answers analysis
questions accurately and in
complete sentences.
/25 points
21 | P a g e