Question

Two objects, one of mass m and the other of mass 2m, are dropped from the top of a building. When they hit the ground Two objects, one of mass and the other of mass 2, are dropped from the top of a building. When they hit the ground the heavier one will have twice the kinetic energy of the lighter one. the heavier one will have 2√ times the kinetic energy of the lighter one. both of them will have the same kinetic energy. the heavier one will have four times the kinetic energy of the lighter one

Answer 1

Answer:

The heavier one will have twice the kinetic energy of the lighter one.

Explanation:

For the objects of mass m and 2 m , kinetic energy is

0.5 m v² and 0.5 (2 m) v² respectively. So kinetic energy of the mass 2 m is Twice that of the object of mass m, since their final velocities are equal.

When an object is dropped from the top of a building ( or from some height), its acceleration is equal to the acceleration due to gravity and has a zero initial velocity. On reaching the ground, the final velocity attained by the object depends only on the gravity and the height of fall, as given by the equation v = √2 g h.

So final velocity is independent of the mass of the object. But kinetic energy  is 0.5 m v² , which shows that it depends on the mass of the object and square of the velocity.