Derek is riding his bike 10 mph. he takes 20 seconds to reach 15 mph. what is his acceleration?
0.25 mph/s
1.25 mph/s
4 mph/s
cannot be determined

4 mph/s cause his change is 5mp in 20 seconds so do 20/5= 4 mph/s

The correct answer is 0.25 mph/s.

Explanation:

The expression for the acceleration is as follows:

Here, a is the acceleration, v is the final velocity and u is the initial velocity.

It is given in the problem that Derek is riding his bike 10 mph. He takes 20 seconds to reach 15 mph.

Calculate the acceleration.

Put t= 20 s, v= 15 mph and u= 10 mph in the above expression.

Therefore, his acceleration is 0.25 mph/s.