Question

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

Answer 1

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

Answer 2

Answer: The correct answer is 0.25 mph/s.

Step-by-step explanation:

The expression for the acceleration is as follows:

`a= (v-u)/(t)`

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.

`a= (15-10)/(20)`

`a= 0.25 mph/s`

Therefore, his acceleration is 0.25 mph/s.