Question

Body travelling with speed of 20km/h applyes brake and reduced to 10km/h in 3 min. Find the acceleration of the body​

Answer 1

Initial speed(u) = 20 km/hr

Final speed(v)= 10 km/hr

Time taken(t) = 3mins = 1/20 hrs

Acceleration of a body is given by:-

a = $\sf\dfrac{v - u}{t}$

a = $\sf\dfrac{10 - 20}{\frac{1}{20}}$

a = -1/2 km/hr

acceleration comes negative

So,

Retardation of a body is 1/2km/hr