Question 31: If the earth stops rotating about its axis, the acceleration due to gravity will remain unchanged at:
Answer: (d) poles
Question 32: The gravitational field in a region is 10 N/kg The work done by gravitational force to shift slowly a particle of mass 1 kg point (1 m, 1m) to a point (2m, – 2m) is:
Answer: (d) + 40 J
Question 33: In previous problem, the work done by external agent is:
Answer: (b) - 40 J
Explanation Since, particle is shifted slowly so, change in kinetic energy is zero.
According to work-energy theorem
W + Wext = 0
Wext = – W = – 40 J
Question 34: The gravitational force in a region is given by
The work done by gravitational force to shift a point mass m from (0, 0, 0) to (x0, y0, z0) is:
Answer: (b) max0y0
Question 35: Let V and E be the gravitational potential and gravitational field at a distance r from the centre of a hollow sphere. Consider the following statements.
(A) The V-r graph is continuous
(B) The E-r graph is discontinuous
Answer: (b) Both (A) and (B) are correct
Explanation The V-r and E-r graphs for a hollow sphere are as follows:
Thus, V-r graph is continuous while E-r graph is discountinuous.
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