If both the mass and radius of the earth decrease by 1%. the value of

The acceleration due to gravity is g=GMR2.The new value of g would be g′=G(0.99M)(0.99R)2=1.01GMR2Thus, g would increase by about 1%. The new escape velocity would beve=2×0.99M×G0.99R=2MGR=veThus, the escape velocity will remain unchanged. The potential energy of a body of mass m on the earth's surface would be−Gm(0.99M)(0.99R)=−GmMRThus, the potential energy will also remain unchanged. Hence, the correct choices are (b) and (d).