Forces and Motion in Elevators

Professor Anderson discusses the concept of normal force and its relationship with gravity. He explains how normal force can be less than gravity on an inclined plane and greater than gravity in an accelerating elevator. The discussion extends to free fall scenarios where normal force becomes zero. A hypothetical scenario of a tunnel through Earth is explored, illustrating gravity's effects and symmetry in motion.

What happens to the normal force when an object is on an inclined plane?

• It disappears completely.

• It becomes greater than gravity.

• It remains equal to gravity.

• It becomes less than gravity.

In a stationary elevator, how do the forces acting on a person compare?

• There are no forces acting.

• Normal force and gravity are equal.

• Normal force is greater than gravity.

• Gravity is greater than normal force.

When an elevator accelerates upwards, how does the normal force change?

• It decreases.

• It remains the same.

• It becomes zero.

• It increases.

According to Newton's second law, what is the relationship between force, mass, and acceleration?

• Force equals mass plus acceleration.

• Force equals acceleration divided by mass.

• Force equals mass times acceleration.

• Force equals mass divided by acceleration.

What happens to the normal force when an elevator cable is cut?

• It becomes greater than gravity.

• It becomes zero.

• It remains equal to gravity.

• It becomes negative.

During free fall, what is the acceleration of a person in an elevator?

• 0 m/s²

• 9.8 m/s² upwards

• 9.8 m/s² downwards

• Infinity

What is the initial acceleration when jumping into a hole through the Earth?

• 0 m/s²

• 9.8 m/s²

• 19.6 m/s²

• Infinity

What happens to gravity as you approach the center of the Earth?

• It decreases to zero.

• It becomes negative.

• It remains constant.

• It increases.

If you could jump through a hole in the Earth, what would your motion be like?

• You would stop at the center.

• You would oscillate back and forth.

• You would fly out the other side.

• You would remain stationary.

What is the effect of air resistance in the hypothetical Earth hole scenario?

• It speeds up the motion.

• It has no effect.

• It slows down the motion.

• It reverses the motion.