Rotational K.E.

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.

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

In the diagram above, two masses, one with mass m, the other with mass M = 2m are resting on a uniform plank of length L that pivots at its midpoint. If the mass m is at the far end of the plank, how far away from the pivot should the mass M be to balance the plank in a horizontal position shown?

• L/2
• L/3
• L/4
• L/6

Tags

NGSS.HS-PS2-1

A cylinder (I=¹/₂mr²) and a hoop (I=mr²) of the same radius and same mass are traveling at the same angular velocity (ω).  What is the ratio of the rotational kinetic energy of the cylinder to the rotational kinetic energy of the hoop?

• 1:1
• 1:2
• 2:1
• 1:4

What is the total kinetic energy of a 3 kg solid disk (I = 1/2mr2) with a diameter of 80 cm rolling at 4 m/s?

• 12 J

• 24 J

• 36 J

• 48 J

Tags

NGSS.HS-PS3-1

You roll a solid sphere of mass m and radius r (I = 2/5mr2) down a ramp from a height of h, if it starts at rest what is its linear speed at the bottom?

• √1.4gh)

• √2gh)

• √3.5gh)

• √5gh)

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

The figure shows scale drawings of four objects, each of the same mass and uniform thickness, with the mass distributed uniformly. Which one has the greatest moment of inertia when rotated about an axis perpendicular to the plane of the drawing at point P?

• A
• B
• C
• D

Three homogeneous ridged bodies -- a solid shere, a solid cylinder, and a hollow cylinder -- are placed at the top of an incline.  If all are released from rest at the same elevation and rolls without slipping, which reaches the bottom first?

• The solid sphere.
• The solid cylinder.
• The hollow cylinder.
• They will all arrive at the same time.

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

The drive chain in a bicycle is applying a torque of 0.850 N ∙ m to the wheel of the bicycle. You can treat the wheel as a thin uniform hoop (or ring) with a mass of 0.750 kg and a radius of 33.0 cm. What is the angular acceleration of the wheel?

• 10.4 rad/s2
• 3.43 rad/s2
• 5.20 rad/s2
• 1.06 rad/s2

Tags

NGSS.HS-PS2-1

At what angle should the force be applied to a wrench to produce the maximum torque?

• 0⁰ to the handle

• 90⁰ to the handle

• 180⁰ to the handle

• 360⁰ to the handle