V K Sally and R Goel Solutions for Chapter: Motion, Exercise 13: Practice Problems

A rubber ball is dropped from a height of $100 \mathrm{m}$, on striking the hard ground rises up to $40 \mathrm{m}$. What is the displacement of the ball?

Two cars starting from a same point move in opposite directions along north-south, such that each covers a distance $x$ in the same time. What is the displacement of the car moving towards south?

A man travels a certain distance with a speed of $50 \raisebox{1ex}{$\mathrm{km}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{h}$}\right.$ and returns back to the starting point with a speed of  $40 \raisebox{1ex}{$\mathrm{km}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{h}$}\right.$. Calculate $\left(\mathrm{i}\right)$ average speed and $\left(\mathrm{ii}\right)$ average velocity of the whole journey. 

A cyclist moves a distance of $30 \mathrm{m}$ from a point $\mathrm{A} \mathrm{to} \mathrm{B}$ in a straight line towards east with a speed of $10 \raisebox{1ex}{$\mathrm{m}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{s}$}\right.$. Then he moves a distance of $40 \mathrm{m}$ from a point $\mathrm{B} \mathrm{to} \mathrm{C}$ in a straight line towards north with a speed of $20 \raisebox{1ex}{$\mathrm{m}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{s}$}\right.$. Calculate average speed, average velocity of the whole journey? 

A bus starts from rest and picks up a velocity of $90 \mathrm{km}/\mathrm{h} \mathrm{in} \frac{1}{2} \mathrm{minute}$. Calculate the uniform acceleration of the bus in $\mathrm{m}/{\mathrm{s}}^2$. Write answer upto two decimal places. 

An aeroplane standing on a runway picks up a speed of $144 \mathrm{km}/\mathrm{h} \mathrm{in} 40 \mathrm{s}$, before taking off. Calculate the uniform acceleration in $\raisebox{1ex}{$\mathrm{m}$}\!\left/ \!\raisebox{-1ex}{${\mathrm{s}}^2$}\right.$ developed by its engine in SI system.

(Write only the magnitude of the answer in the given box)

From the given table, plot the distance-time graph.

From the graph, calculate : $\left(\mathrm{i}\right)$ the average speed, $\left(\mathrm{ii}\right)$ the distance between $1.5 \mathrm{s}$ and $3.5 \mathrm{s}$.

From the given table, plot the distance-time graph. From the graph calculate:

(i) The average speed between $0-3 \mathrm{s}$.

(ii) The average speed between $3 \mathrm{s}-5 \mathrm{s}$.

(iii) The average speed between $5 \mathrm{s}-7 \mathrm{s}$.