ch.13 practice quiz

Question 1

what is true about torque?

Answer 1

1.) it is characterized by direction
2.) it is a vector quantity
3.) it is characterized by magnitude

Question 2

a seesaw is an example of which class of lever?

Answer 2

1st class

Question 3

T/F: the center of gravity of an object/body is always located within the object/body

Answer 3

false

Question 4

T/F: a motionless body is in a state of static equilibrium

Answer 4

true

Question 5

T/F: to achieve static equilibrium, the sum of the torques must equal zero

Answer 5

true

Question 6

in the human body, most of the lever systems formed by muscles performing concentric contractions are which class of lever?

Answer 6

3rd class

Question 7

mechanically, a body behaves as though all of its mass were concentrated __

Answer 7

at its center of gravity

Question 8

what is the term for the perpendicular distance between the line of force and the axis?

Answer 8

moment arm

Question 9

when the mass distribution within an object is not constant, the objects center of gravity __(imagine a baseball bat)

Answer 9

shifts in the direction of greater mass

Question 10

T/F: in order to optimize their takeoff, athletes in sports like high jump and pole vault lower their centers of gravity prior to takeoff

Answer 10

true