an adult weighing 600 N raises the centre of gravity of his body by 0.25 m while taking each step of 1 m length in jogging. If he jogs for 6 km, calculate the energy utilised by him in jogging assuming that there is no energy loss due to friction of ground and air.

An engine is attached to a wagon through a shock absorber of length 1.5 m. The system with a total mass of 50,000 kg is moving with a speed of 36 km h^-1 when the brakes are applied to bring it to rest. In the proces of the system being brought to rest, the spring of the shock absorber gets compressed by 1.0 m. If 90% of energy of te wagon is lost due to friction. calculate the spring constant.

In a shotput event an athlete throws the shotput of mass 10 kg with an initial speed fo 1 ms^-1 at 45^@ from a height 1.5 m above ground. Assuming air resistance to be negligible and acceleration due to gravity to be 10 ms^-2 , the kinetic energy of the shotput when it jst reaches the ground wil be

An alpha particle (_2He^4) is moving directly towards a stationary gold nucleus (_(79)Au^(197)) .The alpha -particle and the gold nucleus may be considered to be solid spheres with the charge and mass concentrated at the centre of each sphere.When the two spheres are just toching,the sepaation of their centres is 9.6 xx 10^(-15) m . the alpha particle and the gold nucleus may be assumed to be an isolatedd system.Calculate for the alpha particle just in contact with the gold nucleus, its electric potential energy.