Read each statement below carefully and state, with reasons and examples, if it is true or false :
A scalar quantity is one that
$(a)$ is conserved in a process
$(b)$ can never take negative values
$(c)$ must be dimensionless
$(d)$ does not vary from one point to another in space
$(e)$ has the same value for observers with different orientations of axes.
A particle moves along a straight line in such a way that it’s acceleration is increasing at the rate of $2 m/s^3$. It’s initial acceleration and velocity were $0,$ the distance covered by it in $t = 3$ second is ........ $m$
The position vector of a particle is given as $\vec r\, = \,({t^2}\, - \,8t\, + \,12)\,\hat i\,\, + \,\,{t^2}\hat j$ The time after which velocity vector and acceleration vector becomes perpendicular to each other is equal to........$sec$