Question

15. A car starting from rest, has a speed of 30 km h-1, at
any one instant. Two second later its speed is 36 km
h-l, and 2 s after that it is 42 km h-1.
(i) If it continues to accelerate like this, what will
be it's speed at 8 s and 9 s after that instant ?
(ii) What was its speed 4 s before its speed was 30
km h-1?
(iii) What is its acceleration in m s-2.​

Answer 1

Answer:

Acceleration = (Final velocity - Initial velocity) / Time taken

Speed in m/s = speed(km/hr) * 1000/3600

30 km/hr = 8.33 m/s, 36 km/hr = 10m/s, 42 km/hr = 11.67 m/s

Acceleration = (10 - 8.33)/2 = 0.835m/s2 

Acceleration = (11.67 - 10)/2 = 0.835 m/s2 

The body moves with a constant acceleration of 0.835 m/s2