As the object moves from point a to point d across the surface, the sum of its gravitational potential and kinetic energies . decreases, onlyb. decreases and then increasesc. increases and then decreasesd. remains the same

d. remains the same

Explanation:

We know that if there is no external resistive force then the total energy of the system remains constant.

The total energy is the summation of kinetic and potential energy.

When an object moves from point A to another point D then the total energy, potential gravitational and kinetic energy will remain same.

Therefore the answer is d.

Explanation:

Here we need to mention the conservation of energy theorem, which states that energy cannot be created or destroyed, just transformed. In other words, the total energy of a system is constant, or the sum of potential and kinetic energy is always constant.

This conservation of energy is possible because when the kinetic energy decreases, the potential energy increases, that's why the sum of them is always constant.

However, there's a case where the total energy is not constant, where there are non conservative forces, like force due to friction, this type of forces subtract energy from the system, which means it won't be constant.

So, assuming that the statements refers to conservative forces only, the right answer is D. remaing the same.