Question

How long would it take a car to accelerate from 20 mph to 60 mph if its acceleration is 20 mph/s?

A. 2.5 s
B. 3 s
C. 2s
D. 1.5 s

Answer 1

Answer: C: 2s

Step-by-step explanation:

lets think about it logically.

If the car is gaining 20 mph every second, and its already at 20:

in 1 second, it will be at 40 mph, (20 + 20).

In 2 seconds, it will be at 60 mph, (40 +20). Boom! answer.

C: 2 seconds.

This is actually easier if you do it with the formula for acceleration, which is:

`a = (v)/(t)`

its actually Δv and Δt, which means, change in velocity over change in time.

basically the equation would be:

20 = 40/x , where x, the time, is what we need. solving for x would give 2, which is the answer we got logically too.