A time-varying force varies with time. As shown in the graph. The force acts on a body of mass $4.0 \mathrm{kg}$. Impulse of the force from $\mathrm{t}=0 \mathrm{to} \mathrm{t}=15 \mathrm{s}$ is $88 \mathrm{N} \mathrm{s}$. Find the speed (in meter per seconds) of mass at $15 s$. Assuming the initial velocity was zero.

A time-varying force varies with time. As shown in the graph. The force acts on a body of mass $4.0 \mathrm{kg}$. Impulse of the force from $\mathrm{t}=0 \mathrm{to} \mathrm{t}=15 \mathrm{s}$ is $88 \mathrm{N} \mathrm{s}$. State the magnitude of initial velocity (in meter per seconds)of the body such that it is brought to rest at $15 \mathrm{s}$.

A boy rides on the scooter pushing on the road with one foot, with a horizontal force that depends on time as shown in the graph.While the scooter rolls a constant force of $25 \mathrm{N}$ opposes the motion. The combined mass of the boy and the scooter is $25 \mathrm{kg}$. Find the speed of the boy after $4 s$, assuming he started from rest.

A boy rides on the scooter pushing on the road with one foot, with a horizontal force that depends on time as shown in the graph.While the scooter rolls a constant force of $25 \mathrm{N}$ opposes the motion. The combined mass of the boy and the scooter is $25 \mathrm{kg}$. Draw a graph to represent variation of boy's speed with time.

A ball of mass $m$is dropped from the height of ${\mathrm{h}}_1$ and rebounds to a height of $h_2$.The ball is contact with the floor for the time time interval $t$. Show that the average net force on the ball is given by $F=m\frac{\sqrt{2g{h}_1}+\sqrt{2g{h}_2}}{t}$

A ball of mass $m$is dropped from the height of ${\mathrm{h}}_1$ and rebounds to a height of $h_2$.The ball is contact with the floor for the time time interval $t$. The average net force on the ball is given by $F=m\frac{\sqrt{2g{h}_1}+\sqrt{2g{h}_2}}{t}$.If ${\mathrm{h}}_1=8 \mathrm{m}$, ${\mathrm{h}}_2=6 \mathrm{m}$, $t=0.125 s$ and $\mathrm{m}=0.250 \mathrm{kg}$. Calculate the average force by the ball on the floor (In newton).

The diagram shows the variation in time of the force exerted on the ball as the ball came into contact with a spring.

For how long was the spring in contact with the ball ?