Answer: a) 7.71 m/s², b) - 6.67 m/s²
Explanation: first thing to note is that
1 mile = 1609.34
1 hour = 3600s
Hence, 100mph to m/s = (100 × 1609.34)/3600 = 44.71 m/s
Initial velocity (u) = 0, final velocity (v) = 44.71 m/s, t = 5.8s, a = acceleration =?
By using newton's laws of motion
v = u + at
44.71 = 0 + a(5.8)
44.71 = 5.8a
a = 44.71/5.8
a = 7.71 m/s²
Question b)
The car is completing a stop which implies that the car is coming to rest, and when a car is coming to rest, the final velocity (v) is zero.
Hence u = 34 m/s, v = 0, a =?, t = 5.1 s
v = u + at
0 = 34 + a(5.1)
a(5.1) = - 34
a = - 34/5.1
a = - 6.67 m/s².
The negative sign beside the acceleration shows that the body is decelerating
