Question

how much kinetic energy does a roller coaster have if its mass is 3000 kg and is moving at 30 m/s

Answer 1

The Kinetic energy of an object is given by:
$E_k= \frac{1}{2}mv^2$

Where m is the mass of the object (kg) and v is the velocity of the object (ms-1)

Substituting in:
$E_k= \frac{1}{2}*3000*30^2 = 1350000J$
Therefore the Kinetic energy of the object is 1.35MJ