We are being asked to calculate the **velocity** of the silver sphere at the moment it hits the ground.

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

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

$\overline{){{\mathbf{E}}}_{{\mathbf{p}}}{\mathbf{=}}{\mathbf{m}}{\mathbf{\times}}{\mathbf{g}}{\mathbf{\times}}{\mathbf{h}}}$

where *m is the mass*

*g is the Earth's gravity (9.81 m/s ^{2})*

*h is the height*

As it is dropped, its **potential energy** is transformed into **kinetic energy**.

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 velocity of the silver 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.)

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Intro to Conservation of Energy concept. You can view video lessons to learn Intro to Conservation of Energy. Or if you need more Intro to Conservation of Energy practice, you can also practice Intro to Conservation of Energy practice problems.

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Based on our data, we think this problem is relevant for Professor Sanov's class at ARIZONA.