Question

Hi, I am having some issues with this physics problem, and it is vital for me to get this problem solved. Can anyone please give me the answer to the problem in the image and tell me how they got the answer with a step by step explanation? I would really appreciate help! ​

Answer 1

Answer:

U = 30 m/s

a = 3 m/s²

Explanation:

"A car accelerating uniformly from rest reaches a maximum speed of U in 10 s.  It then moves with that speed for an additional 20 s.  The distance covered by the car in the 30 s interval is 750 m.  Find U and the acceleration of the car in the first 10 s."

During the first 10 s:

v₀ = 0 m/s

v = U m/s

t = 10 s

The distance covered in this time is the average velocity times time:

Δx = ½ (v + v₀) t

Δx = ½ (U + 0) (10)

Δx = 5U

The distance covered in the next 20 seconds is speed times time:

Δx = 20U

The total distance is 750 m:

5U + 20U = 750

25U = 750

U = 30 m/s

The acceleration during the first 10 seconds is the change in speed over change in time.

a = Δv / Δt

a = (30 m/s − 0 m/s) / 10 s

a = 3 m/s²