Anne releases a stone from a height of 2 meters. She measures the kinetic energy of the stone at 9.8 joules at the exact point it hits the ground. What is the mass of the stone?

a) 0.5 kilograms
b) 0.6 kilograms
c) 0.4 kilograms
d) 0.9 kilograms

Question

Anne releases a stone from a height of 2 meters. She measures the kinetic energy of the stone at 9.8 joules at the exact point it hits the ground. What is the mass of the stone?

a) 0.5 kilograms 
b) 0.6 kilograms
c) 0.4 kilograms
d) 0.9 kilograms

anonymous · Answer

loss of gravitation potential energy = gain in kinetic energy
mgh = KE
rearrange for m
m=KE/gh
m=0.5 kg