Define acceleration. State its SI unit. When is the acceleration zero? Give one example when the body at rest possesses non zero acceleration.

A force of $100 \mathrm{N}$ acts on a body so that the body acquire a velocity of $10 {\mathrm{ms}}^{-1}$ after some time. Now the force of $100 \mathrm{N}$ is replaced by another force F which decelerates the body and body come to the rest then.

A body starts from rest is accelerated uniformly for 30s. If x1, x2, x3 are the distances travelled in first 10s; next 10s and last 10s respectively, then x1 : x2 : x3 is

In the above graph what is the value of acceleration? 

State which of the following situations are possible and give an example for each of these:

An object with a constant acceleration but with zero velocity.

What do you mean by $5 \mathrm{m} {\mathrm{s}}^{-2}$?

State whether the following situation is possible or not and give an example for the case.

An object with a constant acceleration but with zero velocity.

An object is thrown vertically upwards and rises to a height of $20 \mathrm{m}$. Calculate the velocity with which the object was thrown upwards. ($g=10 \raisebox{1ex}{$\mathrm{m}$}\!\left/ \!\raisebox{-1ex}{${\mathrm{s}}^2$}\right.$).

Can be a body be accelerated, if it is moving with constant speed?

Define acceleration.

The direction of acceleration is same as that of _____.

(force/torque)