Circular Motion
Center of Gravity
Rotational Mechanics
Math Practice
Misc.
100
Which has greater linear speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?
What is the outside horse?
100
When a wrench is slid spinning over a frictionless tabletop, its center of gravity follows
What is a straight line?
100
Equation for torque.
What is force times lever arm?
100
The tangential speed at the outer rim of a Ferris wheel is 10 m/s. What is the tangential speed of a position half way from the center to the outer rim?
5 m/s
100
The cause of day and night is the earth's ______.
What is rotation?
200
Which has greater angular speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?
What is neither? They both have the same angular speed (also called rotational speed.)
200
An object will fall over if its center of gravity is
not over its area of support.
200
Best screwdriver to use to turn a screw that is stuck.
What is a wide handle?
200
You sit at the outer rim of a Ferris wheel that rotates at 2 revolutions per minute (RPM). What would your rotational speed be if you were instead clinging to a position halfway from the center to the outer rim?
2 RPM
200
T/F When an object is balanced so that a displacement lowers its center of gravity, the object is said to be in stable equilibrium.
What is false?
300
What is the direction of the force that acts on clothes in the spin cycle of a washing machine?
What is inward? Also called centripetal force which means "center-seeking."
300
Location of the center of gravity in a human.
What is changes as the person moves?
300
Suppose a carnival Ferris wheel has seats that are located halfway between the center and the outside rim. Compared to the ordinary Ferris wheel, where the seats are on the outside rim, your rotational speed on this Ferris wheel would be _____.
What is the same?
300
A meter stick is balanced at the 50.0-cm mark. You tie a 10-N weight at the 15-cm mark. Where should a 30-N weight be placed so the meter stick will again be balanced?
61.7 cm mark
300
The speed a bucket of water must be swung around to keep the water in the bucket if the length of the arm and bucket are .8 m.
What is 2.8 m/s?
400
If you whirl a tin can on the end of a string and the string suddenly breaks, the can will _______________.
The can will fly off, tangent to its circular path.
400
Why can most girls do the chair trick we did in class with very little effort, while most boys cannot?
Most females have a lower center of gravity and so it is supported still by their feet when leaning over. Most males have a higher center of gravity and it is not supported when leaning over.
400
The effect on your weight when the speed on the Gravitron ride increases.
What is increases?
400
Suppose the torque produced by a wrench on a stubborn nut is 30 N·m. If the lever arm is doubled with no change in force, what is the resulting torque?
60 N.m
400
T/F Revolution is caused by moving around an internal axis.
What is false?
500
Definition of centripetal force.
What is the force that makes an object move in a circle?
500
Explain stable, unstable and neutral equilibrium in terms of center of gravity.
Stable - if the object is displaced, the COG will rise. Unstable - if the object is displaced, the COG will lower. Neutral - if the object is displaced, the COG will neither lower or rise.
500
Force that allows a race car to turn on a banked track without friction.
What is the horizontal portion of the weight?
500
A 40-kg boy sits on a seesaw 2.0 m from the fulcrum. What distance from the fulcrum should a 30-kg girl sit in order to balance the seesaw?
2.7 m
500
A student carries a .20 kg lunch tray with .4 kg of food .20 m from the right edge. The tray is held by the left edge .10 m from the fulcrum. The amount of force need to support the tray.
What is 17 N?
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