Deck 12: Linear Kinetics of Human Movement

Question 1

Which quantity is not a force?

A) friction
B) mass
C) weight
D) gravity

Answer 1

mass

Question 2

Which of the following mechanical quantities is not dependent on time?

A) work
B) power
C) kinetic energy
D) velocity

Answer 2

work

Question 3

Which of the following mechanical quantities is evident in explosive track and field events, such as the long jump and the shot put.

A) kinetic energy
B) potential energy
C) mechanical work
D) mechanical power

Answer 3

mechanical power

Question 4

The product of a force and the time during which it acts defines what?

A) momentum
B) velocity
C) acceleration
D) impulse

Question 5

A skater gliding on ice will continue to move in the same direction and with the same speed (in the absence of the action of additional forces). This exemplifies which of the following laws?

A) Newton's first law of inertia
B) Newton's second law of acceleration
C) Newton's third law of action/reaction
D) Newton's law of gravitational force

Question 6

In sporting activities, what amount of friction is desired?

A) large
B) small
C) none
D) depends on the situation

Question 7

Energy of motion is also called what?

A) potential energy
B) kinetic energy
C) strain energy
D) elastic energy

Question 8

Which of the following correctly describes impact?

A) large force applied over a long period of time
B) large force applied over a short period of time
C) small force applied over a long period of time
D) small force applied over a short period of time

Question 9

Which of the following is true of the coefficient of restitution of a racquetball?

A) it depends solely on the type of material of which the ball is made
B) it depends on the size of the ball as well as the type of material
C) it depends solely on how hard the ball is hit
D) it is a number relating to the elasticity of a ball against a particular surface

Question 10

What variable may be described as "the quantity of motion" possessed by an object?

A) force
B) inertia
C) momentum
D) velocity

Question 11

Which of the following relationships is correct?

A) m = F/a
B) F = m/a
C) a = m/F
D) none of the above

Question 12

The capacity for doing work that a body possesses because of its height or position is called what?

A) potential energy
B) kinetic energy
C) moment of inertia
D) mechanical power

Question 13

The higher the jump, the "harder" the landing. This statement reflects which of the following laws?

A) the law of inertia
B) the law of momentum
C) the law of torque
D) the law of action-reaction

Question 14

Which of the following quantities would be different on the moon than on the earth?

A) acceleration due to gravity
B) mass
C) both mass and acceleration
D) neither mass nor acceleration

Question 15

A 500N gymnast performing a giant swing with an angular velocity of 5 rad/sec, exerts 90 Nm of torque on the support bar. How much torque is exerted by the bar on the gymnast's hands?

A) 100 Nm
B) 2500 Nm
C) 590 Nm
D) 90 Nm

Question 16

The principle of conservation of momentum restates which of Newton's laws?

A) inertia
B) acceleration
C) action/reaction
D) gravitation

Question 17

Which of the following pairs of quantities are expressed in the same units of measure?

A) friction and weight
B) work and energy
C) both A and B
D) neither A nor B

Question 18

The 2 variables that determine momentum are

A) velocity and time
B) velocity and mass
C) mass and acceleration
D) velocity and acceleration

Question 19

What determines the time a horizontally projected object remains in the air?

A) weight
B) mass
C) projection height
D) all of the above

Question 20

If an object of constant mass travels with a constant velocity, which statement is true?

A) momentum is constant
B) acceleration is 0
C) both A & B
D) none of the above

Question 21

Which of the following relationships is always true?

A) μ_k < μ_s
B) μ_s < μ_k
C) μ_k = μ_s
D) none of the above

Question 22

The formula for mechanical work is the product of which of the following?

A) force and displacement
B) force and time
C) acceleration and time
D) power and displacement

Question 23

Which of the following statements is true of the amount of horizontal force required to start an object sitting on a horizontal surface in motion?

A) it must be greater than the coefficient of kinetic friction
B) it must be greater than the coefficient of static friction
C) it must be greater than the maximum static friction force
D) it must be greater than the maximum kinetic friction force

Question 24

What happens to momentum when an impulse acts on a system?

A) momentum is conserved
B) momentum is changed
C) impulse does not affect momentum
D) all of the above are possible

Question 25

Which of the following is closest to a perfectly elastic impact?

A) modeling clay dropped on a hard surface
B) modeling clay dropped on a trampoline
C) superball dropped on a hard surface
D) superball dropped on a trampoline

Question 26

How does adding weight to the back of a pickup increase the friction between the tires and the icy road?

A) changes μ_k
B) changes μ_s
C) changes R
D) friction is not increased

Question 27

Negative mechanical work involves which of the following?

A) net torque and angular motion are same direction
B) net torque and angular motion are in different directions
C) concentric muscle contraction
D) none of the above

Question 28

What is/are the direction(s) for vertical ground reaction force?

A) up
B) down
C) lateral
D) all of the above are possible directions

Question 29

Which of the following is/are true statement(s) regarding the law of gravitation?

A) All bodies are attracted to one another with a force proportional to the product of their masses.
B) All bodies are attracted to one another with a force inversely proportional to the square of the distance between them.
C) The law of gravitation ceases to exist outside the earth's atmosphere.
D) both A and B
E) all of the above

Question 30

Which of the following is/are correct formula(s) for mechanical power?

A) P = W/t
B) P = Fd/t
C) P = Fv
D) both A and B
E) all of the above

Question 31

Which of the following affects the coefficient of restitution between a tennis racket and tennis ball?

A) how long the ball has been out of the can
B) how many times the ball has been hit
C) tightness of the grip
D) both A and B
E) all of the above

Question 32

Which of the following would be typical for vertical ground reaction force (GRF) during running?

A) GRF = body weight
B) GRF = 2 X body weight
C) GRF = ½ body weight
D) None of the above

Question 33

Which of the following factors does not affect the amount of friction generated between two dry surfaces?

A) the coefficient of friction between the two surfaces
B) the surface area in contact
C) the reaction force
D) the normal force

Question 34

Which of the following statements is true about the relationship between impact and impulse?

A) impact is always greater than impulse
B) impulse is always greater than impact
C) impacts generate impulses
D) impulses generate impacts

Question 35

When two bodies collide head-on and then continue to travel collectively in the original direction of motion of one of the bodies, what factor determines the direction of collective motion after the collision?

A) the relative momenta of the two bodies
B) the relative masses of the two bodies
C) the relative acceleration of the two bodies
D) the relative weights of the two bodies

Question 36

What type of energy is strain energy?

A) potential
B) kinetic
C) caloric
D) entropic

Question 37

Which of the following is a correct unit of mechanical power?

A) Joules
B) Watts
C) kg-m
D) kg/m

Question 38

Which of the following is a correct unit for linear momentum?

A) N·m
B) N·m/s
C) kg·m
D) kg·m/s

Question 39

Which of the following is a correct unit of mechanical energy?

A) Joules
B) Watts
C) kg-m
D) kg/m

Question 40

How does wearing gloves increase the friction between the hands and the bat?

A) changes μ_k
B) changes μ_s
C) changes R
D) friction is not increased

Question 41

From a mechanical perspective, it is easier to pull an object than to push it.

Question 42

Explain why pulling a heavy object is easier than pushing it, including appropriate formulas in your answer.

Question 43

Newton's law of acceleration demonstrates the relationship between acceleration, ___________________ and ___________________.

Question 44

There are 2 formulas for mechanical power. Show how one formula can be derived from the other and explain the importance of power (relative to the formulas) in sport, dance or rehabilitation.

Question 45

Harder running surfaces result in greater ground reaction forces.

Question 46

An impact resulting in the total loss of velocity would be called a perfectly ___________________ impact.

Question 47

Provide 2 examples in sport, dance or rehabilitation where it is advantageous to increase friction and 2 examples where it is better to decrease friction, including methods used.

Question 48

A motionless object sitting on a motionless surface, with no horizontal force application, has no friction.

Question 49

Newton's law of ___________________ can be restated as the conservation of ___________________.

Question 50

Explain the relationship between linear momentum and linear impulse by providing appropriate formula(s) and examples.

Question 51

Explain the conservation of mechanical energy, including the appropriate formula related to an example in sport, dance or rehabilitation.

Question 52

New blade designs have resulted in extremely low values for the kinetic friction coefficients of ice hockey skates on ice.

Question 53

A number that serves as an index of elasticity for colliding bodies is called coefficient of ___________________.

Question 54

Elite sprinters display greater impulse against the starting blocks than sub-elite sprinters.

Question 55

Two common forces that act to reduce momentum are ___________________ and __________________ __________________.