Conservation of Energy

What is the correct unit for the moment of inertia?

• kg*m
• N/m
• N*m/s
• kg*m^2

If a moment of inertia is increased, what happens to the rate of an object's spin?

• It slows down
• It stays the same because the mass is the same
• It speeds up
• Moment of inertia doesn't affect the spin, the mass does.

What do we not bother using the moment of inertia in rollercoaster problems?

• Too much friction to overcome
• The masses aren't equally distributed.
• The wheels are very small compared to the rest of the coaster.
• Because force weight causes the motion, not moment of inertia.

Because a hollow ball has a higher moment of inertia than a solid ball...

• The solid ball rolls faster
• The solid ball weighs more.
• The solid ball weighs less.
• They both accelerate at the same rate.

We drop a golf ball from 1 meter's height, and it consistently bounces to 73 cm.  This is because...

• Sound and heat are converted to motion.
• Force friction between the table and the golf ball.
• 27% of the energy still goes into movement after the bounce.
• 73% of the energy still goes into the movement after bouncing.

In general, the higher a rollercoaster....

• the faster it can travel
• the ratio between rotational and translation KE increases.
• the less friction force it has
• the slower it moves

What is the unit of the coefficient of friction?

• N/m
• N
• kg*m²
• none

What would be the general formula to find velocity where I=3/4mr^2?

• square root of 6/5gh
• square root of 10/7gh
• square root of 8/7gh
• square root of 2gh

There are three solid balls.  Ball one: large diameter, large mass  Ball two: very small diameters, small mass.
Ball three medium diameter medium mass.  If all are released together on a ramp, which reaches the bottom first?

• Heavy large ball
• Small light ball
• The larges diameter ball
• All at the same time

If a ball moves with slipping down a ramp

• it goes slower than if it had rolled down
• it moves faster than if it had rolled down.
• It doesn't make a difference about friction or not friction.
• Friction slows it down.

Tags

NGSS.HS-PS2-1