Ch12 Exam Questions Linear Kinetics of Human Movement

Basic Biomechanics, 8e (Hall)

Chapter 12 Linear Kinetics of Human Movement

1) Which of the following relationships is correct?

A) m = F / a

B) F = m / a

C) a = m / F

D) none of these answers is correct

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

A) weight

B) mass

C) projection height

D) all of these answers are correct

3) 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 momentum is constant and acceleration is 0

D) none of these answers is correct

4) 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

5) A 500 N 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

6) 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

7) Which quantity is not a force?

A) friction

B) mass

C) weight

D) gravity

8) The 2 variables that determine momentum are

A) velocity and time.

B) velocity and mass.

C) mass and acceleration.

D) velocity and acceleration.

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

A) force

B) inertia

C) momentum

D) velocity

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

A) inertia

B) acceleration

C) action/reaction

D) gravitation

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

A) potential energy

B) power

C) kinetic energy

D) velocity

12) 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

13) 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

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

A) momentum

B) velocity

C) acceleration

D) impulse

15) 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

16) Energy of motion is also called what?

A) potential energy

B) kinetic energy

C) strain energy

D) elastic energy

17) 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

18) 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 friction and weight and work and energy

D) neither friction and weight nor work and energy

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

A) joules

B) watts

C) kg-m

D) kg/m

20) 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 moments 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

21) 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

22) 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

23) 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

24) What type of energy is strain energy?

A) potential

B) kinetic

C) caloric

D) entropic

25) 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 all bodies are attracted to one another with a force proportional to the product of their masses and all bodies are attracted to one another with a force inversely proportional to the square of the distance between them.

E) All of these answers are correct.

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

A) changes μk

B) changes μs

C) changes R

D) friction is not increased

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

A) changes μk

B) changes μs

C) changes R

D) friction is not increased

28) 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

29) 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 these answers are correct

30) 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

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 how long the ball has been out of the can and how many times the ball has been hit

E) all of these answers are correct

32) 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

33) 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 these answers is correct

34) 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 P = W/t and P = Fd/t

E) All of these answers are correct

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

A) joules

B) watts

C) kg-m

D) kg/m

36) Choose the term that describes the constant-magnitude friction generated between two surfaces in contact during motion.

A) friction

B) coefficient of friction

C) maximum static friction

D) kinetic friction

37) Choose the term that describes the number that serves as an index of the interaction between two surfaces in contact.

A) coefficient of friction

B) maximum static friction

C) friction

D) kinetic friction

38) Choose the term that describes the force acting perpendicular to two surfaces in contact.

A) maximum static friction

B) normal reaction force

C) perfectly elastic impact

D) perfectly plastic impact

39) Choose the term that describes the quantity of linear motion.

A) impulse

B) kinetic energy

C) kinetic friction

D) linear momentum

40) Choose the term that describes the product of force and the time interval over which the force acts.

A) impulse

B) kinetic energy

C) kinetic friction

D) linear momentum

41) Choose the term that describes an impact during which the velocity of the system is conserved.

A) maximum static friction

B) impact

C) perfectly elastic impact

D) perfectly plastic impact

42) Choose the term that describes the number that serves as an index of elasticity for colliding bodies.

A) coefficient of friction

B) coefficient of restitution

C) friction

D) impact

43) Choose the term that describes the rate of work production.

A) potential energy

B) power

C) strain energy

D) work

44) Choose the term that describes an energy of motion.

A) kinetic energy

B) kinetic friction

C) potential energy

D) strain energy

45) Choose the term that describes the capacity to do work by virtue of a deformed body's return to its original shape.

A) potential energy

B) power

C) strain energy

D) kinetic energy

46) Newton's law of ________ can be restated as the conservation of ________.

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

48) Newton's law of acceleration demonstrates the relationship between acceleration, ________ and ________.

49) Two common forces that act to reduce momentum are ________ and ________ ________.

50) An impact resulting in the total loss of velocity would be called a perfectly ________ impact.

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

52) 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.

53) 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.

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

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

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

57) Harder running surfaces result in greater ground reaction forces.

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