Two objects, one of mass m and the other of mass 2 m, are dropped from the top of a building. If there is no air resistance, when they hit the ground
A. the heavier one will have twice the kinetic energy of the lighter one.
B. both will have the same kinetic energy.
C. the heavier one will have half the kinetic energy of the lighter one.
D. the heavier one will have four times the kinetic energy of the lighter one.
E. the heavier one will have one-fourth the kinetic energy of the lighter one.
Answer: A. the heavier one will have twice the kinetic energy of the lighter one.
Kinetic energy K = 0.5 mv^2
velocity on reaching the bottom of the ground is
V^2 = 2 gh
so V is independent of the mass
so
KE1 = 0.5 mv^2
KE 2 = 0.5 (2m) * mv^2
KE2 = 2 KE1
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