set 5 MCQ Questions & Answers Detailed Explanation

Question : 1

In an explosion, a body breaks up into two pieces of unequal masses. In this

a) heavier part will have more momentum

b) lighter part will have more momentum

c) both parts will have numerically equal momentum

d) both parts will have equal kinetic energy

Question : 2

If the earth rotates faster than its present speed, the weight of an object will

a) remain unchaged at the equator but decrease at the poles

b) decrease at the equator but remain unchanged at the poles

c) increase at the equator but remain unchaged at the poles

d) remain unchanged at the equator but increase at the poles

Question : 3

Two identical particles move towards each other with velocity 2v and v respectively. The velocity of centre of mass is

a) v/2

b) v/3

c) v

d) zero

Question : 4

Ball bearings are used in bicycles, cars, etc., because

a) the effective area of contact between the wheel and axle is reduced

b) the effective area of contact between the wheel and axle is increased

c) the actual area of contact between the wheel and axle is increased

d) None of the above statements is correct

Question : 5

Statement A :
When a gun is fired it recoils, i.e., it pushes back, with much less velocity than the velocity of the bullet.
Statement B :
Velocity of the recoiling gun is less because the gun is much heavier than the bullet.

a) Both statements are correct.

b) Statement B is correct.

c) Statement A is correct.

d) Both statements are incorrect.

Question : 6

Consider the following statements : If there were no phenomenon of capillarity

1. it would be difficult to use a kerosene lamp
2. one would not be able to use a straw to consume a soft drink
3. the blotting paper would fail to function
4. the big trees that we see around would not have grown on the Earth

a) 2 and 4 only

b) 1, 2 and 3 only

c) 1, 3 and 4 only

d) 1, 2, 3 and 4