A ball of mass 200g falls from a height of 5 m. What will be its kinetic energy when it just reaches theground? (g=9.8 m/s2

The kinetic energy (KE) of an object can be calculated using the formula:

KE = 1/2 * m * v^2

where m is the mass of the object and v is its velocity. However, in this case, we don't know the velocity of the ball when it reaches the ground. But we can use the principle of conservation of energy to solve the problem.

The principle of conservation of energy states that the total energy of an isolated system remains constant. This means that the potential energy (PE) of the ball at the height of 5m will be equal to its kinetic energy when it reaches the ground.

The potential energy can be calculated using the formula:

PE = m * g * h

where m is the mass, g is the acceleration due to gravity, and h is the height.

Substituting the given values:

PE = 0.2 kg * 9.8 m/s^2 * 5 m = 9.8 Joules

Therefore, the kinetic energy of the ball when it just reaches the ground will be 9.8 Joules.