Dhiren M Doshi Solutions for Chapter: Force and Laws of Motion, Exercise 6: Exercises

Name the property of material bodies by virtue of which they resist any change in their state of rest or of uniform motion.  (choose from momentum, inertia, impulse)

A certain force exerted for $0.5 \mathrm{s}$ raises the speed of an object from $2.4 \mathrm{m}/\mathrm{s}$ to $4.9 \mathrm{m}/\mathrm{s}$. Later the same force is applied for $2.5 \mathrm{s}$. How much does the speed of object change in $2.5 \mathrm{s}$?

A body of mass $250 \mathrm{g}$ has a momentum of $7.5 \mathrm{kg} \mathrm{m}/\mathrm{s}$. Calculate the velocity of the body in $\mathrm{m}/\mathrm{s}$.

A car initially at rest, picks up a velocity of $72 \mathrm{km}/\mathrm{h}$ in $20 \mathrm{seconds}$. If the mass of the car is $1000 \mathrm{kg}$. Calculate 

a. the force developed by its engine and 

b. the distance covered by the car in $20 \mathrm{seconds}$.

A car of mass $800 \mathrm{kg}$ moving at $54 \mathrm{km}/\mathrm{h}$ is brought to rest over a distance of $15 \mathrm{m}$. Find the retarding force developed by the brakes of the car.

A $40 \mathrm{kg}$ shell is moving with a velocity of $72 \mathrm{km}/\mathrm{h}$. It explodes into two pieces, of which one piece of mass $15 \mathrm{kg}$ stops immediately. Calculate the velocity of the other piece.  

Nishant is trying to push a heavy box along a rough surface. He is not able to push the box alone. His friend Siddhant, after seeing Nishant helps in pushing the box which causes it to move.

a. Why was Nishant not able to push the box alone?

b. Name the force opposing the movement of the box.

c. What values do we learn from Siddhant?

An elderly person advised Rubina to hold the seat handle while she was travelling in a bus.

a. What will happen to Rubina if the bus stops suddenly?

b. What values are shown by the elderly person?