Answer:
– 2.5 m/s²
Explanation:
We have,
• Initial velocity, u = 180 km/h = 50 m/s
• Final velocity, v = 0 m/s (it stops)
• Time taken, t = 20 seconds
We have to find acceleration, a.
a = (v ― u)/t
a = (0 – 50)/20 m/s²
a = –50/20 m/s²
a = – 5/2 m/s²
a = – 2.5 m/s² (Velocity is decreasing) [Answer]
= 20.436 seconds
Speed = Distance × time
Therefore;
Time = Distance/speed
Distance = 7.50 m, speed = 0.367 m/s
Time = 7.50/0.367
<u>= 20.436 seconds </u>
since the car moves, the force needed to move is greater than the frictional forces opposing it
a = 3.17m/s²