# A ball is thrown into the air with 100 J of kinetic energy, which is transformed to gravitational potential

###### Question:

A ball is thrown into the air with 100 J of kinetic energy, which is transformed to gravitational potential energy
at the top of its trajectory. If it returns to its original level less than 100 J of kinetic energy, the ball
encountered
a. air resistance.
b. gravitational acceleration.
c. a faster descent time.
d. a decrease of its mass.

### Suppose we want to choose 2 letters, without replacement, from the 5 letters A, B, C, D, and E

Suppose we want to choose 2 letters, without replacement, from the 5 letters A, B, C, D, and E...