Question

1. If the Earth shrinks to 50% of its real radius its mass remaining the same, the weight of a body on the Earth will a) decrease by 50% b) increase by 50% c) decrease by 25% d) increase by 300% 2. To project the rockets which of the following principle(s) is /(are) required? a) Newton's third law of motion b) Newton's law of gravitation c) law of conservation of linear momentum d) both a and c​

Answer 1

Answer:

As the mass of the earth remains same, so initially the gravitational acceleration,

g=R2GM and after shrinks g′=(R/2)2GM=4g

% change in weight =mgmg′−mg×100=gg′−g×=g4g−g×100=300 %

Answer 2

Answer:

options d in first and options c in second