Q22 of 28 Page 159

Two bodies of unequal masses are dropped from the top of building. Which of the following is equal for both bodies at any instance?

(a) Speed


(b) force of gravity


(c) potential energy


(d) kinetic energy

(a)

Explanation: Speed of both the bodies will be equal at any instant of time. According to equation of motion .


speed of free falling object doesn’t depend on mass of the object.


While the force of gravity, potential energy, kinetic energy depends upon the mass of object.


More from this chapter

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20

A cycle together with its rider weighs 100kg. How much work is needed to set it moving at 3 m/s.

 21

When the speed of a ball is doubled its kinetic energy

(a) Remains same


(b) gets doubled


(c) Becomes half


(d) becomes 4 times

 23

A man with a box on his head is climbing up a ladder. The work done by the man on the box is

(a) Positive


(b) Negative


(c) Zero


(d) Undefined.

 24

A porter with a suitcase on his head is climbing up steps with uniform speed. The work done by the “weight of the suitcase” on the suitcase is

(a) Positive


(b) Negative


(c) Zero


(d) Undefined