Work Done by a Constant Force and a Variable Force NEET Questions

Physics - Work, Energy, and Power

Work Done by a Constant Force and a Variable Force MCQ Questions


7.
The spring force Fs = −kx is a conservative force because:
A.
It is always directed towards the equilibrium
B.
Work done by it depends only on initial and final displacements, not the path
C.
It can be both positive and negative
D.
It is proportional to displacement
😑 View Answer Rough Work Error
ANSWER :
B. Work done by it depends only on initial and final displacements, not the path
8.
A potential energy function V(x) can be defined for a force only if the force is:
A.
Always constant
B.
Always attractive
C.
Conservative
D.
Non-zero everywhere
😑 View Answer Rough Work Error
ANSWER :
C. Conservative
9.

The minimum work done in pulling up a block of wood weighing 2 kN for a length of 10 m on a smooth plane inclined at an angle of 15° with the horizontal is: (Given: sin15° = 0.2588)

A.

4.36 kJ

B.

5.17 kJ

C.

8.91 kJ

D.

9.82 kJ

😑 View Answer Rough Work Error
ANSWER :

B. 5.17 kJ

10.
A particle moves along a closed loop under the action of gravity. The total work done by gravity is:
A.
mgH (H = height of loop)
B.
2mgH
C.
Zero
D.
−mgH
😑 View Answer Rough Work Error
ANSWER :
C. Zero
11.
Which of the following statements about non-conservative forces is CORRECT?
A.
They always do positive work
B.
Work done by them is path-independent
C.
No potential energy function can be associated with them
D.
They conserve total mechanical energy
😑 View Answer Rough Work Error
ANSWER :
C. No potential energy function can be associated with them
12.
The work done by the gravitational force on an object of mass m moved along two different paths from height h1 to h2 (h2 > h1) is:
A.
mg(h1 − h2) for both paths
B.
Different for different paths
C.
mg(h2 − h1) for both paths
D.
Zero for both paths
😑 View Answer Rough Work Error
ANSWER :
A. mg(h1 − h2) for both paths