Question

1. A motorcycle moving at a constant velocity suddenly accelerates at a rate of 4. 0m/s² to a

speed of 35m/s in 5. 0s. What was the initial speed of the motorcycle?

a) -34m/s

b) -15m/s

c) 15m/s

d) 34m/s

Answer 1

C: 15m/s

Step-by-step explanation:

We know that the motorcycle accelerated at a rate of 4m/s, this means that for every second that it accelerated, it will get 4m/s faster than its original starting speed.

We are told that the motorcycle accelerated at this rate for 5 seconds, this basically means that the motorcycle got faster by 4m/s five times.

Total acceleration from original speed: +4m/s x 5 seconds = 20m/s

Then we are told that after these five seconds have passed, the motorcycle is going at a steady speed of 35m/s, we can therefore calculate the original speed by subtracting the total acceleration from this speed.

Original speed; 35m/s - 20m/s = 15m/s

This means that the answer is C, 15m/s