Linear Kinetics
1. Newton's first law focuses on
a. action-reaction
b. acceleration
c. inertia
d. gravity
e. none of the above
2. Which of Newton's laws is described by the equation F = ma?
a. first
b. second
c. third
d. fourth
e. law of gravitation
3. Which quantity is the same in space as on the earth?
a. weight
b. mass
c. gravity
d. center of gravity
e. moment of inertia
4. When a sprinter uses starting blocks to enhance running performance, which of Newton's laws is best represented by the interaction of the sprinter and the blocks?
a. action-reaction
b. acceleration
c. inertia
d. gravity
e. amplification
5. What is the unit for weight in the International system?
a. pound
b. kilogram
c. newton
d. slug
6. As the mass of an object increases, what happens to its inertia?
a. It decreases.
b. It increases.
c. It stays the same.
d. It weighs more.
e. Mass and inertia are not related.
7. Gravity can be defined as
a. the force with which the earth pulls on an object's mass
b. the amount of force acting over a given area
c. an object's mass per unit volume
d. an object's weight per unit volume
e. a buoyant force
8. If an unbalanced horizontal force is applied to a body that is at rest, the body will
a. stay at rest
b. stay at rest until the unbalanced force is removed
c. accelerate
d. accelerate when the unbalanced force is removed
e. need more information to determine
9. To start in motion an object sitting at rest on a horizontal surface, the horizontal force applied must be
a. greater than the vertical force
b. less than the vertical force
c. greater than the weight of the object
d. less than the weight of the object
e. none of the above
10. An unbelted victim in a car accident will continue to move in the same direction and with the same speed until the dashboard causes a change in motion. This best exemplifies
a. Newton's first law of motion
b. Newton's second law of motion
c. Newton's third law of motiond. the law of force
e. the law of action-reaction
11. If a body of constant mass is traveling with a constant velocity,
a. there must be no force acting on the body
b. there must be no unbalanced force acting on the body
c. there must be force acting on the body
d. there must be an unbalanced force acting on the body
e. need more information to determine
12. If the resultant acceleration of a 2 kg ball is 5.0 m/s/s horizontally, the resultant force must be
a. 0.4 N
b. 2.5 N
c. 7.0 N
d. 10.0 N
e. need more information to calculate
13. Amy is in-line skating. She is rolling forward (north) on a flat section of road at 10 m/s. Her mass is 50 kg. The rolling friction acting on the wheels of her skates is 10 N backward (south). Air resistance creates a 15 N force also acting backward (south) on her. If these are the only horizontal forces acting on Amy, what is her horizontal acceleration as a result of these forces?
Correct Answer:
14. Amy is speedskating. She is gliding forward (north) on the ice at 10 m/s. Her mass is 60 kg. The friction acting on the blade of her skate is 1 N backward (south). Air resistance creates a 5 N force also acting backward (south) on her. If these are the only horizontal forces acting on Amy, what is her horizontal acceleration as a result of these forces?
Correct Answer:
15. If a bag has a mass of 25 kg, how much force must you apply vertically to lift it off of a baggage cart?
a. less than 250 N
b. 250 N
c. greater than 250 N
d. need more information to calculate
16. The maximum limiting friction that can be generated between the bag and the cart is 50 N. You need to slide the bag to the side of the cart. If you apply 50 N horizontally on the bag,
a. the bag will remain motionless
b. the bag will begin to slide
c. the bag will rise off the cart
d. need more information to calculate
17. If you lift up on the bag with 275 N of vertical force, the acceleration of the bag will be
a. 21 m/s/s
b. 11 m/s/s
c. 4 m/s/s
d. 1 m/s/s
e. need more information to calculate
18. According to Newton's third law, when two bodies collide,
a. the forces on each body will be exactly the same
b. the forces on each body will be exactly the same if the mass of each body is approximately the same
c. the force applied to each body will be the same size
d. the force applied to each body will be the same size if the mass of each body is approximately the same
e. none of the above
19. An unbalanced horizontal force of 200 N is applied to a wrestler of mass 100 kg. The horizontal acceleration of the wrestler will be
a. 200 m/s/s
b. 100 m/s/s
c. 2 m/s/s
d. 1 m/s/s
e. need more information to calculate
20. If an unbalanced horizontal force is applied to a body that is moving horizontally, the body will
a. stay moving until the unbalanced force is removed
b. start to increase speed
c. start to decrease speed
d. change direction of movement
e. need more information to determine
21. The skip of the Canadian curling team exerts a horizontal force of 10 N against the 20 kg rock during his delivery. At this instant, the rock is sliding across the ice, and the skip is not exerting any vertical force on it. The coefficient of static friction between the rock and the ice is 0.08. The coefficient of dynamic friction between the rock and the ice is 0.05. What is the horizontal acceleration of the rock?
Correct Answer:
22. A 500 N gymnast performs a stationary handstand on the high bar. How much force is exerted by the bar on the gymnast's hands?
a. 50 N
b. 100 N
c. 500 N
d. 2500 N
e. need more information to calculate
23. A high jumper with a body weight of 820 N exerts an average vertical force of 1640 N down on the floor for 0.75 s. The average vertical force exerted on the jumper by the floor is
a. 615 N
b. 820 N
c. 1230 N
d. 1640 N
e. 3280 N
24. When a dancer pushes off from the floor, the observed acceleration is less for the floor than for the dancer because
a. the floor has less inertia than the dancer
b. the dancer has less inertia than the floor
c. the reaction force applied to the dancer is greater than the action force applied to the floor
d. the action force applied to the dancer is greater than the reaction force applied to the floor
e. The accelerations are actually the same, but the audience is only interested in the motion of the dancer.
25. A 60 kg dancer applies a horizontal force of -800 N on the dance floor. The dancer's acceleration will be
a. -7.5 m/s/s
b. 7.5 m/s/s
c. -13.33 m/s/s
d. 13.33 m/s/s
e. need more information to calculate
26. Which of the following is not a force?
a. friction
b. mass
c. weight
d. gravity
27. Units of momentum could be
a. m/s
b. N
c. joules
d. N·m/s
e. kg·m/s
28. Which quantity causes a change in linear momentum?
a. impulse
b. impact
c. force
d. work
e. none of the above
29. The product of a force and the time during which it acts defines
a. linear momentum
b. linear velocity
c. linear acceleration
d. linear impulse
e. linear displacement
30. If you increase the time during which a constant force is applied to an object, what effect does this have on the impulse given to the object?
a. It increases the impulse.
b. It decreases the impulse.
c. It doesn't affect the impulse.
d. It causes the impulse to equal zero.
e. none of the above
31. If an athlete moves faster, what happens to her momentum?
a. It increases.
b. It decreases.
c. Velocity has no impact on momentum.
d. Her momentum equals zero.
e. It converts to impulse.
32. An example of using impulse to safely decrease momentum would be
a. catching a ball with an extended arm
b. landing with the hips, knees, and ankles locked
c. landing on a mat when pole vaulting
d. leaning into a punch thrown at your face
e. all of the above
33. The product of a body's mass and its linear velocity defines
a. linear momentum
b. linear impulse
c. linear torque
d. linear inertia
e. mechanical work
34. The principle of conservation of momentum restates
a. Newton's law of gravitation
b. Newton's first law
c. Newton's second law
d. Newton's third law
e. Newton's fourth law
35. Ben's mass is 100 kg. He lands from a jump. His initial vertical velocity when his feet first touch the ground is 4 m/s downward. What is the average normal contact force that acts on Ben's feet during this landing if he comes to a stop in 0.20 s?
Correct Answer: