Chapter 6 physics class 11

A wall acted upon by a force of 20 N does not move. The work done is

• 20J

• 10J

• 0J

• None of the above

When force retards the motion of the body, the work done is

• Zero

• Negative

• Positive

• Both negative and positive

No work is done if

• Force and displacement are mutually perpendicular

• Force is zero

• Displacement is zero

• All of these

A particle is taken around a circle by application of force. The work done is

• Zero

• Positive non - zero

• Negative non - zero

• None of these

Assertion : The work done is moving a body over a closed loop is zero for every force in in nature.

Reason : Work done depends on nature of force

• Assertion is correct ; reason is correct but reason is not the correct explanation of the assertion

• Assertion is correct ; reason is correct and reason is the correct explanation of assertion

• Assertion is correct ; reason is incorrect

• Assertion is incorrect ; reason is correct

If a motorcyclists skids and stops after covering a distance of 15m.The stopping force acting on the motorcycle by the road in 100 N, the the work done by the motorcycle on the road is

• 0J

• 750J

• -1500J

• 1500J

A boy pushes a toy box 2.0 m along the floor by means of a force of 10 N directed downward at an angle of 60° to the horizontal. The work done by the boy

• 12J

• 8J

• 6J

• 10J

A boy carrying a box on his head is walking on a level road from one place to another and keeping it down on the ground is doing work. This statement is

• Correct

• Incorrect

• Partly correct

• Cannot say

Joule is named after the British _________ James Prescott Joule

• Scientist

• Physicist

• Biologist

• None of the above

Work done is scalar quantity even though force and displacement are _________ quantity

• Scalar

• Scalar and vector

• Vector

• None