Look at the diagram above and answer the following questions :

(a) When a force is applied through the free end of the spring balance A the reading on the spring balance A is $15 \mathrm{gwt}$. What will be the measure of reading shown by spring balance B?

Look at the diagram above and answer the following questions :

(b) Write reason for your answer.

Look at the diagram above and answer the following questions :

(c) Name the force which balance A exerts on balance B and the force of balance B on balance A.

State Newton's second law of motion. Write it's mathematical expression. How can you state first law from it?

A body of mass $\text{'}\mathrm{m}\text{'}$ is moving with a velocity $\text{'}\mathrm{u}\text{'}$. When a force is applied on it for time $\text{'}\mathrm{t}\text{'}$ its velocity increases to $\text{'}\mathrm{v}\text{'}$. Write the expressions for initial and final momentum.

A body of mass $\text{'}\mathrm{m}\text{'}$ is moving with a velocity $\text{'}\mathrm{u}\text{'}$. When a force is applied on it for time $\text{'}\mathrm{t}\text{'}$ its velocity increases to $\text{'}\mathrm{v}\text{'}$. Write the expressions for

(b) change in momentum

A body of mass $\text{'}m\text{'}$ is moving with a velocity $\text{'}u\text{'}$. When a force is applied on it for time $\text{'}t\text{'}$ its velocity increases to $\text{'}v\text{'}$. Write the expressions for 

$\left(c\right)$  rate of change of momentum.