Download Fall Final Review 15-16 File

Midterm Review I – Kinematics
AP Physics I
Essential Knowledge & Skills (Can I / Do I):
1.
2.
3.
4.
5.
6.
Know and apply the definitions of displacement, velocity, and acceleration
Calculate the displacement, time, velocity, or acceleration of an object using kinematics
Plot the displacement, velocity, or acceleration of an object from a given graph or initial conditions
Recognize the significance of the slope of such graphs
Interpret the physical meaning of such graphs
Interpret other physical pictures of motion
Terms: displacement, velocity, acceleration, slope
Examples: Complete all examples in the space provided. Show all work including units.
1. The position vs. time graph of three objects moving along the x-axis is shown below. Use the graph to
determine the following.
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a) Which object is accelerating at t = 1 s?
x (m)
b) Find the velocity of all three objects at
t = 5 s.
c) At what time do A and B have the same position?
d) How far from the origin is object A after 20 s?
A
4
3
B
2
e) At what time will B reach the origin?
C
1
f) The initial velocity of object C is 0 and the acceleration
is constant. Find the acceleration of object C at t = 1 s.
1
2
3
4
5
t (s)
A
x (m)
B
C
2
v (m/s)
a (m/s )
0
0
10
0
2. Three different graphs are shown above for three different objects. Determine each of the following:
a) Which objects are accelerating?
b) Which objects have a negative initial velocity?
c) Which objects have a negative acceleration?
d) Which objects have a negative initial position?
AP Physics I Midterm Review
Fall 2015
3. An object starts at rest and then moves with constant acceleration of 2.5 m/s2. Determine each of the
following
a) How far has the object moved from its starting position after 25 s?
b) How long does it take for the object to reach a velocity of 24 m/s?
c) How far does the object go before it has a velocity of 24 m/s?
v (m/s)
2
0
2
4
6
8
10
t (s)
-2
4. The graph above shows the velocity of an object as a function of time. Determine each of the
following:
a) What is the object’s initial velocity?
b) What is the acceleration of the object at t = 3 s?
c) What is the acceleration of the object at t = 5 s?
d) What is the acceleration of the object at t = 10 s?
e) At what times is the object at rest?
f) How far from its starting position is the object after 2 s?
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AP Physics I Midterm Review
Fall 2015
5. A ball is dropped from the top of a building 15 m tall.
a) Find the time needed for the ball to reach the ground.
b) Determine the velocity of the ball just before it hits the ground
c) On the axis below, plot the position of the ball as a function of time and the velocity of the ball as a
function of time. Be sure to label the axis appropriately.
x (m
v (m/s)
+x
v
t
6. The picture above shows the motion of
an object at equal time intervals. What can
be concluded about the velocity of the
object?
A) Its velocity is constant
B) Its velocity is increasing
C) Its velocity is decreasing
D) Nothing can be determined from the picture
7. Given the graph of velocity vs. time for a
moving object above, what is the initial
velocity of the object?
a) 0
b) negative
c) positive
d) cannot be determined
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AP Physics I Midterm Review
Fall 2015
Midterm Review II – Forces & Newton’s Laws
AP Physics I
Essential Knowledge & Skills (Can I / Do I):
1. Know, understand, and apply the three laws of motion
2. Understand and interpret the property of inertia; the tendencies of any moving or stationary
object: when the net force is zero the velocity is constant
3. Know the relationship between force, mass, and acceleration (including graphical) and apply
Newton’s 2nd Law to find the force or acceleration acting on an object
4. Understand and apply the concept of a reaction force
5. Draw and interpret Free Body Diagrams
6. Apply Hooke’s Law and find the spring constant of a spring
7. Know that weight is a force and the appropriate SI unit of weight
Terms: force, net force, weight, Newton, inertia, reaction force, friction,
Examples: Complete all examples in the space provided. Show all work including units.
1. Newton’s First Law of Motion is often referred to as the Law of Inertia.
a) Define the term inertia.
b) What is needed to change the motion of an object (accelerate it)?
c) What is the natural tendency of an object at rest?
d) What is the natural tendency of an object in motion?
e) What relationship exists between acceleration, mass, and your answer to b? Draw two graphs
showing these relationships. This is Newton’s 2nd Law.
f) Whenever a force is exerted on an object, what does that object do to whatever exerted the force?
Completely explain Newton’s 3rd Law.
2. A man stands in an elevator on a scale at rest. The man has a mass of 100 kg.
a) What is the man’s weight?
b) Draw a free body diagram showing all the forces on the man while he is at rest. What is his net force?
c) What normal force is exerted on the man while he’s at rest?
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AP Physics I Midterm Review
Fall 2015
d) The elevator now accelerates upwards and the scale reads 1500 N. Draw a new free body diagram
showing the forces.
e) Calculate the net force acting on the man.
f) Calculate the acceleration of the man.
g) If he accelerates at this rate the entire elevator trip, how long would it take him to reach the top floor,
35 m above his starting position?
h) How long does it take him to get there?
3. Marcy pulls a friction block that has a mass of 3.5 kg at a constant speed of 2.0 m/s. Using a force
sensor, she finds the horizontal force she exerts to be 28 N.
a) Draw a free body diagram of the block. What is the net force on the block (you only need information
given in the first part!)
b) Find the force of friction on the block.
c) Assume Marcy now pulls with a force of 38 N and calculate the acceleration of the block. The force of
friction doesn’t change when she pulls harder.
d) Calculate the magnitude of the force Marcy would have to pull with to accelerate the block at 4.5 m/s 2.
e) If Marcy exerts no force at all while the block is moving, what is the acceleration of the block?
4. Humberto (mass = 125 kg) is standing on ice skates on a frictionless sheet of ice facing his ice
dancing partner Isabella (mass = 65 kg). Humberto pushes Isabella and notices he accelerates
backwards at the same time. Using his Olympic accelerometer, he measures his acceleration to be 1.0
m/s2. Assume the direction Humberto accelerated in to be the positive direction.
a) Why does Humberto accelerate when he pushes Isabella?
b) Draw a free body diagram of both ice dancers while Humberto is accelerating.
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AP Physics I Midterm Review
Fall 2015
c) Calculate the force exerted by Humberto on Isabella.
d) Calculate Isabella’s acceleration.
e) After pushing Isabella, Humberto slides backwards with a velocity of 2.5 m/s. Calculate Isabella’s
velocity after being pushed by Humberto.
f) How long were the two ice dancers in contact with each other (exerting a force on each other)?
g) Describe the motion of the two ice dancers after they are no longer in contact with each other.
5. A mass of .50 kg is hung from an ideal spring whose spring constant is 5.0 N/m. How far will
the spring be stretched from its unstretched length? Use g = 10 m/s2.
a) 0
b) .50 m
c) 1.0 m
d) 5.0 m
6. A 0.500 kg ball with a speed of 4.0 m/s strikes a stationary 1.0 kg target. If momentum is
conserved, what is the total momentum of the ball and target after the collision?
a) 0 kg·m/s
b) .5 kg·m/s
c) 1.0 kg·m/s
d) 2.0 kg·m/s
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AP Physics I Midterm Review
Fall 2015
Questions 7 – 9.
The diagram below shows a 4.0 kg cart moving to the right and a 6.0 kg cart moving to the left on a
horizontal frictionless surface. When the two carts collide they lock together.
7. The magnitude of the total momentum of the two-cart system after the collision is
a) 0.0 kg·m/s
b) 6.0 kg·m/s
c) 15 kg·m/s
d) 30 kg·m/s
8. The magnitude and direction of the velocity of the two-cart system after the collision is
a) .6 m/s right
c) 1 m/s right
e) 1.5 m/s right
b) .6 m/s left
d) 1 m/s left
f) 1.5 m/s left
9. Which of the following are conserved in this situation?
c) momentum
a) velocity
d) force
b) kinetic energy
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AP Physics I Midterm Review
Fall 2015
Midterm Review III – Vectors & Projectiles
AP Physics I
Essential Knowledge & Skills (Can I / Do I):
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Understand the definition of a vector and a scalar and differentiate between the two
Use trigonometry to add and resolve vectors
Understand and apply the definition of a projectile
Draw / recognize the free body diagrams and motion diagrams of a projectile
Calculate the range (horizontal distance) of a projectile and calculate its height at any given time
Understand that an object in circular motion is accelerating because it is changing directions and
thus a centripetal force must be acting on such an object
Calculate the period, frequency, and linear velocity of an object moving in circular motion
Identify the centripetal force on an object
Calculate the centripetal acceleration and force on an object in circular motion
Understand the centrifugal effect and the effects of inertia in a rotating frame of reference
(apparent force)
Examples: Complete all examples in the space provided. Show all work including units.
1. Consider the two displacement vectors given below and complete / evaluate each of the following.
a = 2.0m north
b = 2.0m east
a) What two parts does every vector have (by definition)?
b) What is the significance of a negative vector?
c) Find the resultant:
i) 3a =
iii) a + b =
ii) -2b =
iv) a - b =
2. A cannon is launched from the top of a cliff 45 m tall with an initial velocity of 57 m/s.
a) Is the cannon ball a projectile? Explain why or why not.
b) In which axis of motion is the cannon ball’s velocity considered constant? Explain why.
c) Draw a free body diagram of the cannon after it has been fired and before it hits the ground.
d) Draw a motion diagram showing the vertical velocity vectors, the horizontal velocity vectors, and the
acceleration of the cannon ball.
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AP Physics I Midterm Review
Fall 2015
e) Calculate the time the cannon ball is in the air.
f) Calculate the horizontal distance the cannon ball travels before hitting the ground.
3. A cannon ball is fired from the ground with an initial velocity of 57 m/s at a 35° angle relative to the
horizontal. The ball lands at the same height it was fired from.
a) Resolve the velocity vector into its horizontal and vertical components.
b) Find the time that the cannon ball is in the air.
c) Calculate the horizontal distance the ball travels before reaching the ground.
d) Sketch a graph of horizontal (x) displacement vs. time and another graph of vertical (y) displacement
vs. time.
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AP Physics I Midterm Review
Fall 2015
Midterm Review Part IV
AP Physics I
Answer all parts in the space provided.
1. A man walks to the north. A police office with a radar gun measures his position as a function of time.
His data are shown in the table.
Distance (m)
6
5
4
3
2
a) Plot his data on the graph
b) Determine the average velocity of the man.
x (m)
c) Determine the acceleration of the man.
Time (s)
21.2
17.1
15.9
13.2
12.0
6
4
d) Draw a picture and sketch a graph of an object accelerating.
2
4
8
12
16
20
t (s)
e) Draw a free body diagram of an object moving at constant velocity.
2. An airplane drops a bomb while flying straight and level. Ignoring any outside forces, where will the
bomb be in relationship to the plane when it hits the ground?
3. A team of dogs pulls a sled at a constant velocity by exerting a force of 1500 N on the sled. The sled
has a mass of 300 kg.
a) Draw a free body diagram of the sled.
b) Calculate the force of friction acting on the sled.
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AP Physics I Midterm Review
Fall 2015
c) How hard would the dogs have to pull to accelerate the sled at 3.0 m/s 2?
4. Humberto hangs a ball of mass 2.5 kg from a string.
a) While the ball is at rest, calculate the force of tension in the string.
b) Humberto then accelerates the ball upwards at 5 m/s2. Calculate the new force of tension in the string.
5. A car has a mass of 850 kg and is moving to the north with a velocity of 40 m/s.
a) Calculate the momentum of the car.
b) Calculate the kinetic energy of the car.
c) What impulse would be needed to stop the car?
d) How much work would be needed to stop the car?
6. Bill and Ted each have a mass of 125 kg. Ted runs up a flight of stairs 15 m high in 8.5 seconds,
while Bill takes 12.5 s.
a) Calculate the work done by each person.
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AP Physics I Midterm Review
Fall 2015
8. A roller coaster has a mass of 700 kg and is pulled up to the top of the first hill, at point A, which is 90
m above the ground. Assume the track to be frictionless.
a) Calculate the gravitational potential energy of the roller coaster at point A
b) Calculate the kinetic energy of the roller coaster at the bottom of the hill
c) Calculate the speed of the roller coaster at the bottom of the hill
d) Suppose the track had the same dimensions, but was not frictionless. How would your answers to
parts a), b), and c) change?
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