Question

Define acceleration and give its SI unit when is acceleration of the body negative ?give two example of situation in which acceleration of the body is negative

Answer 1

change in velocity per unit time is called acceleration.. it's SI unit is m/s^2 i.e. meter per second square
acceleration of body is negative in such cases
when we apply brakes on a moving vehicle...

Answer 2

Acceleration is the rate of change of velocity with respect to time. So it can be represented as
a = dv/dt
Where dv = change in velocity
and dt = change in time.
SI unit of acceleration becomes m/s^2 .