When an apple falls from a tree what happens to its gravitational potential energy just as it reaches the ground ? After it strikes the ground ? `(AS_(7))`

What is meant by gravitational potential energy ? Deduce an expression of the total energy of a planet in its orbit.

A body of mass 10 kg falls from a height of 10 m. What will be its kinetic energy just before it touches the ground ? Prove that, this kinetic energy is equal to the potential stored at the initial position of the body. [g=980 cm *s^(-2) ]

Given the value of ground state energy of hydrogen atom as -13.6 eV. Find out its kinetic and potential energy in the ground and second excited states.

Two bodies having masses m_(1) and m_(2) are dropped from heights h_(1) and h_(2) respectively. They reach the ground after times t_(1) and t_(2) and strike the ground with velocities v_(1) and v_(2) respectively. Choose the correct relations from the following:

The ground state energy of hydrogen atom is -13.6 eV. what are the kinetic and potential energies of the electron in this state ?

From the top of a tower, 80 m high from the ground, a stone is thrown in the horizontal direction with a velocity of 8ms^(-1) . The stone reaches the ground after a time 't' and falls at a distance of 'd' from the foot of the tower. Assuming g=10ms^(-2) , the time t and distance d are given respectively by