After head on elastic collision between two balls of equal masses , one is observed to have a speed of $3\,\,m/s$ along positive $x-$ axis and the other has a speed of $2\,\,m/s$ along negative $x$ axis. The original velocities of the balls are
$-2\,\,m/s\,\,$ and $\,\,+3\,\,m/s$
$+2\,\,m/s\,\,$ and $\,\,+3\,\,m/s$
$-3\,\,m/s\,\,$ and $\,\,+2\,\,m/s$
$+3\,\,m/s\,\,$ and $\,\,-2\,\,m/s$
A rope is used to lower vertically a block of mass $M$ by a distance $x$ with a constant downward acceleration $\frac{g}{2}$. The work done by the rope on the block is
$F = 2x^2 - 3x - 2$. Choose correct option
In an elastic collision of two particles the following quantity is conserved
The energy required to accelerate a car from $10 \,m/s$ to $20\, m/s$ is how many times the energy required to accelerate the car from rest to $10\, m/s$
The work done by a force $\vec F\, = \,( - \,6{x^3}\,\hat i)N$ , in displacing a particle from $x = 4\,m$ to $x = -\,2\,m$ is .............. $\mathrm{J}$