COMEDK202510 May 2025Evening ShiftPhysicsGravitationActual
If the radius of earth were to shrink by two percent, its mass remaining the same, the acceleration due to gravity on the earth's surface would
Options
- AIncrease by (4 % )
- BIncrease by (2 % )
- CDecrease by (4 % )
- DIncrease by (1 % )
Correct answer
A. Increase by (4 % )
Step-by-step solution
The acceleration due to gravity g on the surface of the earth is given by the formula g = GM R^2 , where G is the gravitational constant, M is the mass of the earth, and R is the radius of the earth. Given that the mass M remains constant, g is inversely proportional to the square of the radius, g R⁻² . Taking the logarithmic derivative of the relation g = GM R⁻² , we get dg g = -2 dR R . The radius shrinks by two percent, which means dR R = -0.02 . Substituting this value into the expression for the fractional cha