Question

a) A box in an upward moving elevator is being pushed across the floor with a constant force.

1) Friction is doing positive work on the box. True or False

2) The pushing force is doing negative work on the box. True or False

3) The normal force on the box is doing positive work on the box. True or False

4) If there is net positive work on the box parallel to the floor, the kinetic energy of the box will increase. True or False

5) Gravity does positive on the box. True or False

6) If the elevator, initially moving with a constant speed, begins accelerating down, the frictional work will become more negative for a given displacement. True or False

b) Work, kinetic energy and potential energy are scalars and are expressed in units of Joules. True or False

Answer 1

Answers :

a) A box in an upward moving elevator is being pushed across the floor with a constant force.

1) Friction is doing positive work on the box. False

2) The pushing force is doing negative work on the box. False

3) The normal force on the box is doing positive work on the box. True

4) If there is net positive work on the box parallel to the floor, the kinetic energy of the box will increase. True

5) Gravity does positive on the box. False

6) If the elevator, initially moving with a constant speed, begins accelerating down, the frictional work will become more negative for a given displacement. True

b) Work, kinetic energy and potential energy are scalars and are expressed in units of Joules. True