If the velocity $v$ of a particle moving along a straight line decreases linearly with its displacement $s$ from $20\,ms ^{-1}$ to a value approaching zero at $s=30\,m$, then acceleration of the particle at $s=15\,m$ is $........$
$\frac{2}{3}\,ms ^{-2}$
$-\frac{2}{3}\,ms ^{-2}$
$\frac{20}{3}\,ms ^{-2}$
$-\frac{20}{3}\,ms ^{-2}$
Read each statement below carefully and state with reasons and examples, if it is true or false
A particle in one-dimensional motion
$(a)$ with zero speed at an instant may have non-zero acceleration at that instant
$(b)$ with zero speed may have non-zero velocity.
$(c)$ with constant speed must have zero acceleration.
$(d)$ with positive value of acceleration must be speeding up.
The velocity of a body depends on time according to the equation $v=\frac{t^2}{10}+20$. The body is undergoing
The displacement of a particle after time $t$ is given by $x = \left( {k/{b^2}} \right)\left( {1 - {e^{ - bt}}} \right)$ where $b$ is a constant. What is the acceleration of the particle?
A body under the action of several forces will have zero acceleration
The distance-time graph of a particle at time $t$ makes angle $45^{\circ}$ with the time axis. After one second, it makes angle $60^{\circ}$ with the time axis. What is the average acceleration of the particle?