Assertion : For looping a vertical loop of radius, $$r$$ the minimum velocity at lowest point should be $$\sqrt{5 g r}$$.
Reason : In this event the velocity at the highest point will be zero.
Assertion : A beam of charged particles is employed in the treatment of cancer.
Reason : Charged particles on passing through a material medium lose their energy by causing ionization of the atoms along their path.
Assertion : A spring of force constant $k$ is cut into two pieces having lengths in the ratio 1 : 2. The force constant of series combination of the two parts is $$\frac{3 k}{2}$$.
Reason : The spring connected in series are represented by $$k=k_1+k_2$$
Assertion : The total kinetic energy of a rolling solid sphere is the sum of translational and rotational kinetic energies.
Reason : For all solid bodies, total kinetic energy is always twice of translational kinetic energy.