Give examples to distinguish
$(i)$ Distance and displacement.
$(ii)$ Speed and velocity.
$(iii)$ Acceleration and retardation.
$(i)$ If one states that' the car has travelled $100 m ^{\prime}$, it means that it is the distance travelled by the car. But if one states that 'car has travelled $100\, m$ due north' it means that the displacement of the car is $100\, m$ towards north.
$(ii)$ If a body starts its motion from a point and comes back to its initial position after a a al positon a a certain time, the displacement is zero, the average velocity is also zero. but the total distance travelled is not zero and, therefore the average speed is not zero.
$(iii)$ The motion of a car in a busy market is with variable velocity. In such a case, if the velocity of the body increases with time, the motion is said to be accelerated while if the velocity of the body decreases with time, the motion is said to be retarded
By giving an example, prove that rest and motion are relative terms.
How can you find the distance travelled by body in uniform motion from the velocity$-$time graph ?
An object is dropped from rest at a height of $150\, m$ and simultaneously another object is dropped from rest at a height $100 \,m$. What is the difference in their heights after $2\,\sec $ if both the objects drop with same accelerations ? How does the difference in heights vary with time ?
Can you suggest real life examples about the motion of a body from the following velocity$-$time graphs ?
A motor car slows down from $72\, km h ^{-1}$ to $36\, km h^{-1}$ over at distance of $25\, m$. If the brakes are applied with the same force calculate $(i)$ total time in which car comes to rest $(ii)$ distance travelled by it.