Which of these describes an endothermic process?
a. when lithium is placed in water, the temperature of the container increases.
b. the combustion of kerosene releases heat.
c. when barium hydroxide is mixed with ammonium chloride, ice crystals form on the outside of the container.
d. the reaction of trinitrotoluene with oxygen releases heat and light.

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?