Download B. Multiple Choice Questions

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NAME:______________________
Test A: Dynamics
Date: ________________
Physics
Period ____
Mrs. Burns
A. PROBLEM SOLVING: Do all of the following problems. SHOW ALL WORK!
1. A 60 kg water skier, initially at rest, accelerates at a rate of 2.3 m/s2. If the friction force between the
skis and the water is 200-N, what is the tension in the rope?
2. A block is lifted off of the ground, starting at rest.
a. Draw a motion diagram.
b. Draw a free body diagram.
c. Show the direction of net force.
d. Which force is bigger: weight or Tension?
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3. A 65 kg person stands in an elevator, initially moving at 8 m/s. Determine the average force of the floor
on her body as she stops over a 10-m distance.
4. A 835-g box initially rests on a wooden table. Ignore friction between the table and the box. The box is
attached to a massless string that passes over a small frictionless pulley. A 600-g mass hangs from the
other end of the string. What is the acceleration of the system?
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B. Multiple Choice Questions
DIRECTIONS: Select the BEST answer for each of the following questions. Enter your choice on the
Scantron.
1. Why is a moving 80 kg steel ball difficult to stop in a weightless condition?
A.) It isn't really weightless.
B.) There is no friction in a weightless situation.
C.) The ball is unable to accelerate
D.) The 80 kg. ball has a lot of inertia.
2. What objects are affected by the law of inertia?
A.) moving objects
B.) objects at rest
C.) accelerating objects
D.) all objects
3. What is the one force that always acts on all objects on or near the earth no matter what state of motion
exists?
A.) friction
B.) mass
C.) velocity
D.) gravity
4. Block A is heavier than Block B. The force F is the same in both configurations. The surface is frictionless.
The acceleration of Block A
A.) is larger than Block B.
A
B.) is smaller than Block B.
F
C.) is the same as Block B.
D.) can not be determined.
E.) none of the above.
F
B
5. “Every interaction produces a pair of forces that are equal in magnitude but opposite in direction.” This is
regarded as which of Newton’s laws of motion?
A.) first
B.) second
C.) third
D.) fourth
6. “An object will not change its speed or direction unless an unbalanced force acts on it.” This is regarded as
which of Newton’s laws of motion?
A.) first
B.) second
C.) third
D.) fourth
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7. Which object has the greatest inertia?
A.) a 5.0-kg object moving at a speed of 5.0 m/s
B.) a 10.-kg object moving at a speed of 3.0 m/s
C.) a 15-kg object moving at a speed of 1.0 m/s
D.) a 20.-kg object at rest
A man drags a box with increasing speed, using a rope. Compare the sizes of the forces in the next 3
questions.
8. Compare the tension on the cart to friction between the cart and ground.
A.) tension on the cart is bigger than friction
B.) tension on the cart is equal to friction
C.) tension on the cart is smaller than friction
D.) Impossible to tell.
9. Compare the tension on the cart to the tension on the person.
A.) tension on the cart is bigger than tension on the person
B.) tension on the cart is equal to tension on the person
C.) tension on the cart is smaller than tension on the person
D.) Impossible to tell.
10. Compare the normal force on the cart from the ground to the normal force of the ground on the cart.
A.) normal force on the cart from the ground is normal force of the ground on the cart
B.) normal force on the cart from the ground is equal to normal force of the ground on the cart
C.) normal force on the cart from the ground is smaller than normal force of the ground on the cart
D.) Impossible to tell.
11. What is the magnitude of the force needed to keep a 60.-newton cart moving across level, frictionless
surface in a straight line at a constant speed of 2.0 meters per second?
A.) 0.0 N
B.) 40. N
C.) 51. N
D.) 60. N
E.) 120 N
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12. Which diagram represents a box in equilibrium?
A.)
C.)
B.)
D.)
13. Which body is in equilibrium?
A.) a satellite orbiting Earth in a circular orbit
B.) a ball falling freely toward the surface of Earth
C.) a car moving with a constant speed along a straight, level road
D.) a projectile at the highest point in its trajectory
14. A bus windshield exerts a force on a bug. What is the reaction force?
A.) The bug stops moving.
B.) The bug exerts a force on the windshield.
C.) The windshield pushes back on the bus.
D.) The bus slows down.
15. A cart initially rests on a wooden table as shown. Ignore friction between the table and the box. The box is
attached to a massless string that passes over a small frictionless pulley. If the hanging mass is equal to the
cart mass, then the acceleration is
A.) Equal to gravity (10 m/s2)
B.) Equal to ½ g (5 m/s2)
C.) Less than 10 m/s2 but greater than ½ g (5 m/s2)
D.) Less than ½ g (5 m/s2) but greater than zero (0)
E.) Equal to zero (0)
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