Work, Energy and Power

Question 1

Work done by a constant force is maximum when the angle between force and displacement is:

• A0°
• B30°
• C60°
• D90°

Question 2

A force of 20 N acts at 60° to the horizontal and moves an object 3 m horizontally. The work done is:

• A60 J
• B30 J
• C51.96 J
• D20 J

Question 3

A force of 10 N acts on an object that moves 4 m perpendicular to the force. The work done by this force is:

• A40 J
• B20 J
• C0 J
• D-40 J

Question 4

A person carries a bag horizontally at constant height. Considering only the upward force exerted by the person on the bag, the work done by this force is:

• APositive because the bag moves
• BNegative because gravity acts downward
• CZero because force is perpendicular to displacement
• DEqual to the weight multiplied by the distance

Question 5

A person pushes a rigid wall with a force of 200 N for 10 seconds, but the wall does not move. The work done on the wall is:

• A2000 J
• B200 J
• C20 J
• D0 J