Question

1- A ball starts (from zero speed) rolling down an incline plane (without slipping). What does the angular velocity depend on as it reaches the bottom of the incline?

A- The length of the incline.

B- The mass of the sphere.

C- The height of the incline.

D- The radius of the sphere.

________

2 -To open a door, a person pushes first at the midpoint of the door; then he pushes at the doorknob (edge of the door). Which force exerts the greater torque?

A- The force applied at the doorknob exerts the greater torque.

B- Both forces exert equal nonzero torques.

C- Both forces exert zero torques.

D- The force applied at the midpoint of the door exerts the greater torque.

Answer 1

1.The angular velocity depends on the height of the incline and the radius of the sphere.

C=>The more the initial potential energy, the more the final kinetic energy.

D=> suppose 2 different sized solid, balls are to roll down the incline, they need to get to the bottom in the same amount of time. And a small ball has to do more rotations to get to the bottom, so it'll have higher angular velocity.

2.A ,the force applied at the door knob exerts the greater torque .

The outer edge proives more leverage.You exert the force on the door knob at right angles to the door,away from hinges.