Question

When a car driver travelling at a speed of 10 m/s applies brakes and brings the car to rest in 20 s, then the
retardation will be:
Select one:
a. Negative 0.5 m/s2
O b. Negative 2 m/s2
c. Positive 0.5 m/s2
d. Positive 2 m/s2
A car of mass 1000 kg is moving with a velocity of 10 m/s. If the velocity-time graph for this car is a
horizontal line parallel to the time axis, then the velocity of the car at the end of 25 s will be:
Select one:
a. 25 m/s​

Answer 1

Answer:

1) a     2) 10 m/s

Explanation:

1) Initial Speed (u) = 10 m/s, final speed (v) = 0 m/s, t = 20 s, a = ?

a = (v - u) / t

  = (0 - 10) / 20

a = - 0.5 m/s^2

2) As the velocity - time graph is straight line parallel to time axis velocity is constant. so at time 25 s the velocity is 10 m/s