Draw a velocity versus time graph for a body which starts to move with velocity $'u^{\prime}$ under a constant acceleration $'a'$ for time $t$. Using this graph derive an expression for distance covered $'S'$ in time $'t^{\prime}$
The graph is as shown
The area under the graph is the area of the rectangle $OACD$ plus the area of the triangle ABC on top of it as shown in figure. The rectangle has a height $u$ and a length $t$. This area is the distance travelled by the object.
Hence, $S=u t+\frac{1}{2} \times t \times(v-u)$ $....(1)$
But from the expression $v=u+a t,$ we have
at $=v-u$. Substituting in equation $(1),$ we have
$S=u t+\frac{1}{2}(a t) t=u t+\frac{1}{2} a t^{2}$
A moving body is covering a distance directly proportional to the square of time. The acceleration of the body is
When is an object in motion considered to be a point object ?
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 ?
Explain the following type of motion with one example of each
$(i)$ Acceleration is positive
$(ii)$ Acceleration is negative
$(iii)$ Acceleration is zero.
Area under velocity$-$time graph is equal to the