# Problem: Consider the two spheres shown here, one made of silver and the other of aluminum. The spheres are dropped from a height of 2.1 m.What is the kinetic energy of the aluminum sphere at the moment it hits the ground? (Assume that energy is conserved during the fall and that 100% of the sphere’s initial potential energy is converted to kinetic energy by the time impact occurs.)

###### FREE Expert Solution
93% (156 ratings)
###### FREE Expert Solution

We are being asked to calculate the kinetic energy of an aluminum sphere at the moment it hits the ground.

The aluminum sphere has an energy E which is the total of its potential and kinetic energy.

Before the aluminum sphere is dropped, all of its energy is potential energy. Potential energy is given by the formula:

where:

m is the mass

g is the Earth's gravity (9.81 m/s2)

h is the height

93% (156 ratings)
###### Problem Details

Consider the two spheres shown here, one made of silver and the other of aluminum. The spheres are dropped from a height of 2.1 m.

What is the kinetic energy of the aluminum sphere at the moment it hits the ground? (Assume that energy is conserved during the fall and that 100% of the sphere’s initial potential energy is converted to kinetic energy by the time impact occurs.)