Question

A woman pulls a crate up a rough, inclined plane at constant speed. Which one(s) of the following statements concerning this situation is (are) correct? Group of answer choices The woman does positive work in pulling the crate up the incline. The work done on the crate by the gravitational force is zero joules. The work done on the crate by the normal force of the plane is zero joules. The Net work done on the crate is zero joules. The kinetic energy of the crate does not change.

Answer 1

Answer:

1.The woman does positive work in pulling the crate up the incline.

TRUE

3. The work done on the crate by the normal force of the plane is zero joules.

TRUE

4.The Net work done on the crate is zero joules.

TRUE

5. The kinetic energy of the crate does not change.

TRUE

Explanation:

We analyse each statement:

1.The woman does positive work in pulling the crate up the incline.

The scalar product between the this force and the displacement is positive, then the Work is positive.

TRUE

2.The work done on the crate by the gravitational force is zero joules.

The scalar product between the gravitational force and the displacement is negative, then the this Work is negative (different to zero)

FALSE

3. The work done on the crate by the normal force of the plane is zero joules.

This force is perpendicular to the displacement, then this work is zero.

TRUE

4.The Net work done on the crate is zero joules.

The crate has a constant speed, because the Net Force is zero. Then the Net Work is zero too.

TRUE

5. The kinetic energy of the crate does not change.

As the velocity remains constant the kinetic energy does not change (kinetic energy is proportional to the square of the velocity)

TRUE