Types of energy:

Potential Energy (Ep) comes from gravity. An object must be above the ground (have height) to have potential energy.

Ep = mgh where m is mass in kg, g is the acceleration due to gravity (9.8, but 10 often used), and h is vertical height above the ground.
An object can be moving or at rest. The speed of an object doesn't affect its potential energy, only its height.

Kinetic Energy (Ek) comes from motion. An object must be moving to have kinetic energy.

Ek = (1/2)mv², where m is mass in kg and v is velocity in m/s. An object can be above the ground and still have Ek, if it is moving.

Potential Elastic Energy (PEel) comes from spring or other elastic materials.

PEel = (1/2)kx², where k is the spring constant in N/m and x is the distance the spring is compressed or stretched.

Work (W) is how forces transfer, give, or remove energy. Work can be positive or negative. Work changes an object's energy.

W = Fd, where F is a force in Newtons and d is the distance the force acts on the object in m. Not all forces acting (pushing or pulling) do work on an object. A force that pushes but doesn't move an object (like pushing down on an object on a table or holding onto the object) does no work on the object because it doesn't change the object's energy. So, if a force is acting at an angle, use W = FdcosӨ, where Ө is the angle between the force and the direction the object is moved by the force.