Question

A stone is thrown straight up in the air. If g represents the acceleration due to

gravity, which one of the following statments about the stone is false?
When the stone reaches the top of its flight, its acceleration is still g.
As the stone rises, its potential energy decreases.
When the stone reaches the top of its flight, its energy is zero.
As the stone rises, it is accelerated downward.
As the stone rises, its kinetic energy decreases.

Answer 1

The correct false statement is;

As the stone rises, its potential energy decreases

Step-by-step explanation:

When the stone is thrown straight up into the air, the initial velocity, u, progressively decreases according to the following equation;

v = u - g·t

Where;

v = The final velocity

g = The acceleration due to gravity = 9.81 m/s²

t = The time taken

Therefore whereby, the kinetic energy. K.E. is given by the equation , K.E. = 1/2 × m × u², as u reduces, the kinetic energy reduces

However, the potential energy, P.E. is given as P.E. = m × g × h

Where;

h = Height

m = The mass of the stone

Therefore, as the stone rises, the potential energy increases.