Why does the Energy column not specify the energy type?

Ihave a density of 1.61g/cm^3 and a mass of 28g. find the missing value

On a frictionless air track, a blue glider with mass 0.200 kg is moving to the right with a speed of 8.00 m/s. it strikes a red glider that has mass 0.600 kg and that is initially at rest. after the collision, the blue glider is moving to the left with a speed of 3.00 m/s.(a) what are the magnitude and direction of the velocity of the red glider after the collision? (b) is this collision elastic?

An object is placed in front of a concave mirror between the pole and the focus of the mirror, what is the nature of the image formed by the mirror