Use the KE and GPE equations to solve for speed or height depending on the situation.
A 1-kg model airplane has 12.5 joules of kinetic energy and 98 joules of gravitational potential energy. What is its speed? What is its height?
speed: 5 m/s
height: 9.99 m
kinetic energy = 12 * mass * velocity squared
since speed does not specify direction as velocity does, we can take the value of 5m/s for speed.
gravitational potential energy = mass * gravitational field strength * height
assuming the airplane is flying above Earth, the gravitational field strength is 9.81N/kg.