Deck 21: Impact

Question 1

How can a diver slow down the speed of rotation?

Answer 1

extend body-increase moment of inertia

Question 2

Although an object in motion has no weight in a weightless environment, which of the following does it still possess?

A) mass
B) momentum
C) both a & b
D) none of the above

Answer 2

both a & b

Question 3

Discuss some of the problems that occur in prolonged weightlessness. Include a discussion of both neuromuscular and anatomical considerations.

Answer 3

bone mineral loss, "space sickness", balance

Question 4

Why would a coach recommend a "tighter" tuck to enable the gymnast to get all the way around?

A) angular velocity will decrease
B) angular displacement will decrease
C) moment of inertia will decrease
D) mass will decrease

Question 5

How might a gymnast start the swinging motion without help when hanging motionless from the still rings?

Question 6

About which point does an unsupported body rotate?

A) the center of gravity
B) the center of torque
C) the part of the body last in contact with the surface
D) the point of force application
Short Answer Questions

Question 7

How may the height of the swing of a pendulum be increased?

A) increase radius on downswing, decrease on upswing
B) increase radius on downswing, increase on upswing
C) decrease radius on downswing, decrease on upswing
D) decrease radius on downswing, increase on upswing

Question 8

At what point in a giant swing should a gymnast release the high bar in order to do a trick?
Justify your answer.

Question 9

What determines the terminal velocity of a body in free fall?

A) the surface area presented to the airflow
B) the speed of the fall
C) the position of the body in the air
D) the wind velocity

Question 10

Why is it easier to rotate in a tuck position than a pike position?

A) angular displacement is less
B) angular momentum is less
C) angular velocity is greater
D) linear acceleration is greater

Question 11

Where is the potential energy of a pendulum the greatest?

A) at the bottom of the swing
B) at the top of the swing
C) half way up the swing
D) half way down the swing

Question 12

Which of the following is responsible for movement in a pendulum?

A) the force of gravity
B) momentum
C) reaction forces
D) centripetal and centrifugal forces

Question 13

What will make it difficult for an astronaut to walk for exercise in a weightless environment?

Question 14

What determines the path of the center of gravity of the body in a nonsupport activity?

A) the force of projection
B) the angle of the hip joint
C) the height of projection
D) the angle of projection

Question 15

How might a diver or gymnast initiate a twist about the vertical axis once airborne and rotating forward about the horizontal axis?

A) turn the head away from the rotating direction
B) tilt the body by raising the arm in the direction of the twist
C) tilt the body by raising the arm opposite the twisting side
D) the twist must be started before take off