Work and Friction Concepts

This module explains the concept of work, highlighting that it can be positive or negative. Positive work occurs when force and displacement are in the same direction, as shown in examples of a boy pushing a table and a child pulling a toy cart. Negative work is discussed in the context of friction, where the force opposes displacement. The module details how to calculate work done by forces, including the net work done on an object, by considering both positive and negative contributions.

What is the main difference between positive and negative work?

• Positive work requires more energy than negative work.

• Positive work is done when force is applied, while negative work is done when no force is applied.

• Positive work is done when force and displacement are in the same direction, while negative work is done when they are in opposite directions.

• Positive work is always greater than negative work.

In the example of the boy pushing a table, what type of work is being done?

• Negative work

• No work

• Positive work

• Zero work

What happens to the work done when a force acts in the opposite direction of displacement?

• The work done is negative.

• The work done is doubled.

• The work done is positive.

• The work done is zero.

How does friction affect the work done on a moving object?

• Friction decreases the total work done.

• Friction has no effect on the work done.

• Friction increases the positive work done.

• Friction only affects the speed of the object.

What is the result of the frictional force on the carton box?

• It results in no work.

• It results in negative work.

• It results in zero work.

• It results in positive work.

How is the total work done on an object calculated when friction is involved?

• By ignoring the negative work.

• By adding the positive and negative work.

• By subtracting the negative work from the positive work.

• By multiplying the positive work by the negative work.

What does the negative sign in the work done by friction indicate?

• The friction is acting in the same direction as the applied force.

• The friction is acting in the opposite direction to the applied force.

• The friction is increasing the work done.

• The friction is not affecting the work done.

What is the net force on the carton box if the applied force is greater than the frictional force?

• The net force is the difference between the applied force and the frictional force.

• The net force is equal to the frictional force.

• The net force is equal to the applied force.

• The net force is zero.

How can the net work done on an object be calculated?

• By considering only the applied force.

• By considering the displacement only.

• By considering only the frictional force.

• By considering the net force and the displacement.

What is the significance of the net work done on an object?

• It determines the mass of the object.

• It determines the direction of the object's motion.

• It determines the speed of the object.

• It determines the total energy transferred to the object.