Question

If a stone is thrown out of an accelerated train, then acceleration of the stone at any instant depends on

A. force acting on it at that instant  
B. acceleration of the train
C. Both (A) & (B)
D. None of these
Answer :   force acting on it at that instant
Solution :
Since force at a point at any instant is related to the acceleration at that point, at that instant and acceleration is determined only by the instantaneous force and not by any history of the motion of the particle. Therefore, the moment the stone is thrown out of an accelerated train, it has no horizontal force and acceleration, if air resistance is neglected.

Releted MCQ Question on
Basic Physics >> Laws of Motion

Releted Question 1

A ship of mass $$3 \times {10^7}\,kg$$   initially at rest, is pulled by a force of $$5 \times {10^4}\,N$$   through a distance of $$3m.$$ Assuming that the resistance due to water is negligible, the speed of the ship is

A. $$1.5 m/sec.$$
B. $$60 m/sec.$$
C. $$0.1 m/sec.$$
D. $$5 m/sec.$$
Releted Question 2

The pulleys and strings shown in the figure are smooth and of negligible mass. For the system to remain in equilibrium, the angle $$\theta $$ should be
Laws of Motion mcq question image

A. $${0^ \circ }$$
B. $${30^ \circ }$$
C. $${45^ \circ }$$
D. $${60^ \circ }$$
Releted Question 3

A string of negligible mass going over a damped pulley of mass $$m$$ supports a block of mass $$M$$ as shown in the figure. The force on the pulley by the clamp is given by
Laws of Motion mcq question image

A. $$\sqrt 2 \,{\text{Mg}}$$
B. $$\sqrt 2 \,{\text{mg}}$$
C. $$\sqrt {{{\left( {M + m} \right)}^2} + {m^2}} g$$
D. $$\sqrt {{{\left( {M + m} \right)}^2} + {M^2}} g$$
Releted Question 4

The string between blocks of mass $$m$$ and $$2m$$ is massless and inextensible. The system is suspended by a massless spring as shown. If the string is cut find the magnitudes of accelerations of mass $$2m$$ and $$m$$ (immediately after cutting)
Laws of Motion mcq question image

A. g, g
B. $$g,\frac{g}{2}$$
C. $$\frac{g}{2},g$$
D. $$\frac{g}{2},\frac{g}{2}$$

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