The gravity shown in this example, is how gravity can affect everyday sports such as tennis and how the tennis ball is hit with the force of gravity.
Elastic is a force that a material is able to return to it's original shape after being stretched. This is an example of an elastic force, a wrestling match and how the elastic ropes like the ones from the trampoline are being stretched and used to protect the wrestlers from hitting a hard surface when pushed back or hurt. It bounces them back up.
This is an example of friction is how a sled is moving over snow and ice. This is one of many ways friction is created.