Question

The acceleration of a body is 3m/s2, what does it mean? What is the acceleration of a body moving with a uniform velocity, why? A car moving with a velocity of 15 m/s comes to rest after 5 seconds. Calculate its acceleration.

Answer 1

Answer:

Explanation:

• Acceleration is the rate of change of velocity.

• If the acceleration of a body is 3m/s² , it means that a body moves with velocity 3m/s per unit time.

• Acceleration = $\frac{final velocity-initial velocity}{time}$

given that the body is at uniform velocity [ finalvelocity=initial velocity=v ]

acceleration = $\frac{v-v}{t}$ = $\frac{0}{t}$ = o

That is the acceleration of a body moving with uniform velocity is 0.

• Now we have to find the acceleration of car moving with velocity 15m/s which comes to rest after 5s

initial velocity, u = 15m/s

final velocity, v   = 0

time, t = 5s

acceleration = $\frac{v-u}{t}$

                   = $\frac{0-15}{5}$

                   = $\frac{-15}{5}$

                   = -5

it is negative acceleration or retardation