Download According to Newton`s ______ law, an object with no net force

PHYSICS
FINAL EXAM REVIEW
FIRST SEMESTER (01/2012)
UNIT 1 —Motion
P2.1 A Calculate the average speed of an object using the change of position and elapsed time.
P2.1B Represent the velocities for linear and circular motion using motion diagrams (arrows on strobe
pictures).
P2.1C Create line graphs using measured values of position and elapsed time.
P2.1D Describe and analyze the motion that a position-time graph represents, given the graph.
P2.1g Solve problems involving average speed and constant acceleration in one dimension.
P2.2A Distinguish between the variables of distance, displacement, speed, velocity, and acceleration.
P2.2B Use the change of speed and elapsed time to calculate the average acceleration for linear motion.
P2.2C Describe and analyze the motion that a velocity-time graph represents, given the graph.
P2.2e Use the area under a velocity-time graph to calculate the distance traveled and the slope to calculate the
acceleration.
1.
(P2.1A) The picture below shows a ball rolling along a table at 1 second time intervals. What is the objects average
velocity after 6 seconds?
2. (P2.1A) A car traveled along a straight road at +50 mi/h for 3.0 hours and then traveled on the same road at +35 mi/h
for 1.5 hours. What was the car’s average velocity over the entire trip?
3. (P2.1B) Answer the following questions regarding the motion diagrams of a ball rolling below.
a. Which of the following diagrams shows the ball rolling
with a constant velocity?
b. Which of the following diagrams shows the ball rolling
with a positive acceleration?
c. Which of the following diagrams shows the ball rolling
with a negative acceleration?
d. Which of the following diagrams shows the ball rolling
with a zero acceleration?
4. (P2.1C) Make a position time graph for each object in the table above.
Time
(s)
0
1
2
3
4
5
Position (m)
Object A
5
5
5
5
5
5
Position (m)
Object B
0
1
3
5
7
9
5. (P2.1D)Answer the following questions using the position time graph below.
a. What is the average velocity between 0 and 5 seconds?
b. What is the average velocity between 0 and 10 seconds?
c. What is the average velocity between 0 and 20 seconds?
d. What is the instantaneous speed between 5 and 10
seconds?
6. (P2.1g) A child can push a shopping cart with an average velocity of 1.5 m/s west. How long would it take the child to
push the cart down an aisle with a length of 9.3 m?
7. (P2.1g) It took 3.5 hours for a train to travel the distance between two cities at a speed of 120 miles/hr. How many
miles lie between the two cities?
8. (P2.1g) A cat falls off the top of a dresser that is 2 meters above the ground. How long does it take to reach the
ground?
9. (P2.2A) Which of the following are vectors? Which of the following are scalars?
a. Distance
e. Velocity
b. Time
d. Acceleration
c. Displacement
g. Mass
d. Speed
10. (P2.2A) The length of a football field is 100 yards. A football player runs the entire length of the field and back in 24
seconds.
a. What is the distance and the displacement of the football player?
b. What is the speed and the velocity of the football player?
11. (P2.2B) With an average acceleration of –0.50 m/s2, how long will it take a cyclist to bring a bicycle with an initial
velocity of +13.5 m/s to a complete stop?
12. (P2.2B) A car is accelerating at a rate of 5 m/s2, if its initial velocity is 6 m/s, what is its velocity after 4 s?
13. (P2.2B) A ball is dropped from rest from a high building. What is the ball’s velocity after 3 s? (Ignore air resistance).
14. (P2.2C) Draw a velocity time graph of a ball that is thrown straight up into the air and then returning to its original
height.
15. (P2.2e) Use the velocity time graph below to answer the following questions:
a. What is the displacement of the object between
2 s and 6 s?
b. What is the acceleration of the object at 3 s?
UNIT 2 — Two-Dimensional Motion and Forces
P2.2g
P3.2d
P3.4e
Apply the independences of the vertical and horizontal initial velocities to solve projectile motion
problems.
Calculate all the forces on an object on an inclined plane and describe the object’s motion based on the
forces using free-body diagrams.
Solve problems involving force, mass and acceleration in two dimensional projectile motion restricted to
an initial horizontal velocity with no initial vertical velocity (e.g., a ball rolling of a table).
16. (P2.2g) A stone is thrown horizontally off a cliff. Assuming no air resistance:
a. Describe what happens to the horizontal and vertical velocities of the stone as it falls.
b. What is the direction of the acceleration of the stone at each moment as it falls?
17. (P2.2g) A person traveling on a train that is moving west at a constant speed throws a ball straight up into the air. The
person and the train continues to travel on a straight horizontal track and air resistance is ignored. Where will the ball
fall?
18. (P3.2d) A 50 kg box is at rest on a friction-less ramp. The ramp is at an angle of 25° to the ground.
a. What is the normal force of the ramp on the box?
b. What is the net force acting on the box?
19. (P3.2d) A 45 kg child slides down a frictionless slide at the park. The slide is inclined at an angle of 30° to the
horizontal.
a. What is the normal force acting on the child?
b. What is the net force acting on the child?
20. (P3.4e) A cannon that is 15 m high shoots a ball horizontally with an initial speed of 10 m/s. Assuming no air
resistance, how far away from the cannon will the ball land?
21. (P3.4e) Two balls, a GREEN and a WHITE, roll horizontally off a table that is 2 m above the ground. The GREEN
ball has an initial speed of 10 m/s and the WHITE ball has an initial speed of 20 m/s. At what time will each ball take
to reach the ground (assume no air resistance)?
22. (P3.4e) A plane flying horizontally at a constant speed releases a projectile. Where will the plane be when the
projectile strikes the ground (assume no air resistance)?
UNIT 3 — Dynamics
P3.2A
P3.2C
P3.3A
P3.4A
P3.4C
Identify the magnitude and direction of everyday forces (e.g., wind, tension in ropes, pushes and pulls,
weight).
Calculate the net force acting on an object.
Identify the action and reaction force from examples of forces in everyday situations (e.g., book on a
table, walking across the floor, pushing open a door).
Predict the change in motion of an object acted on by several forces.
Solve problems involving forces, mass, and acceleration in linear motion (Newton’s second law).
23. (P3.2A) Give examples of contact forces and field forces (a.k.a. forces at a distance or non-contact forces).
24. (P3.2A) What is the normal force?
25. (P3.2A) A 245 N crate is at rest on the floor. A person attempts to push it across the floor. The coefficient of static
friction between the floor and the crate s 0.40. What is the maximum force of static friction between the crate and the
ground?
26. (P3.2A)
a.
b.
c.
Draw a free body diagram for each of the following situations:
A sled at rest.
A sled moving at a constant speed to the right.
A sled accelerating to the right.
27. (P3.2C) An object that is falling towards the earth without the presence of air resistance is accelerating back to the
earth. Does the acceleration increase, decrease, or remain the same during the fall?
28. (P3.2C) A motorcycle is slowing down in the forward direction. What is the direction of the net force acting on the
motorcycle?
29. (P3.2C) The forces acting on a sailboat are 390 N north and 180 N east. The boat has a total mass of 270 kg. What
is the magnitude of the resultant (net) force?
30. (P3.2C) Two forces acting on a 5 kg object are 7 N and 10N. The angle between the forces can be varied. What is
the range of possible magnitudes of the net (resultant) force acting on the object?
31. (P3.3A) Describe Newton’s Third Law of Motion.
32. (P3.3A) Identify the action-reaction forces for the following situations:
a. Book on a table
b. Pushing open a door
c. Collision between small car and a large truck
33. (P3.4A) Describe Newton’s First Law of Motion.
34. (P3.4A) What type of force is required to change an object’s velocity or direction?
35. (P3.4A) The object to the right has four forces acting on it. The object was initially at rest.
Which direction does the object move when the forces are applied?
36. (P3.4A)
a.
b.
c.
d.
A 60 kg person stands on a scale in an elevator.
What does the scale read when the elevator is moving up at a constant speed?
What does the scale read when the elevator is moving down at a constant speed?
What does the scale read when the elevator is accelerating downward at 1.5 m/s2?
What does the scale read when the elevator is accelerating upward at 1.5 m/s 2?
37. (P.3.4A) Describe what happened to the person’s scale reading in c and d above.
38. (P3.4C) Describe Newton’s 2nd Law of Motion.
39. (P3.4C) A 5 kg object accelerates at 2 m/s2. What is the net force acting on the object?
40. (P3.4C) A weightlifter applies a constant 1040N force upward to a barbell. The barbell has a mass of 100kg. What is
the acceleration of the barbell?
41. (P.3.4C) Describe the relationship between mass and weight of an object when placed on two different planets.
42. (P3.4C) How does the mass of an object change when an objects weight is measured on the moon and on earth?
43. (P3.4C) Solve for the weight of a person whose mass is 100 kg if the acceleration due to gravity on the planet they
are standing on is one-quarter that of the earth.
UNIT 4 – Momentum
P3.3b
P3.4g
P3.5a
Predict how the change in velocity of a small mass compares to the change in velocity of a large mass
when the objects interact (e.g., collide)
Explain how the time of impact can affect the net force (e.g., air bags in cars, catching a ball).
Apply conservation of momentum to solve simple collision problems.
44. (P3.3b) A small car collides head on with a large truck. Describe what happens to each object’s change in velocity
(acceleration) during the collision.
45. (P3.3b) In a collision, why is it safer to be in a larger car rather than a smaller car? (Answer based on the concept of
momentum)
46. (P3.4g) A 0.046 kg golf ball resting on a tee is struck by a golf club with a force of 2500 N over a time interval of
0.0005 s. Calculate the speed of the golf ball immediately after it is hit.
47. (P3.4g)A 0.10 kg lump of clay is moving to the right at 15 m/s. It hits a wall and stops. The impact lasts for 0.003s.
a. If the time of impact was increased, what would happen to the average force on the clay?
b. If the time of impact was decreased, what would happen to the average force on the clay?
48. (P3.4g) What is the purpose of an air bag in a car during a crash?
49. (P3.4g) A 12 kg ball is initially at rest. A force is applied to
the ball over a small amount of time, shown in the graph.
What is the ball’s change in velocity when the force is applied?
F
(N)
200
100
0
0
0.2
0.4
0.6
0.8
1.0
t (s)
50. (3.5a) A train car moving to the right at 10 m/s collides with a parked train car. They stick together and roll along the
track. If the moving car has a mass of 8,000 kg and the parked car has a mass of 2,000 kg, what is their combined
velocity after the collision?
51. (P3.5a) A 2800 kg truck collides with a 2000 kg car which was at rest. After they collide, they move off together at
7.0 m/s. Assuming no friction, what was the initial speed of the truck?
52. (P3.5a) A red bumper car (m = 220 kg) moving at 3.00 m/s runs into a stationary blue bumper car (m = 280 kg). After
the collision, the red bumper car has bounced backwards at 0.40 m/s. What is the blue bumper car’s speed just after
the collision?