Answer:
43.3 m/s.
Step-by-step explanation:
Assuming the potential energy is due to the gravitational potential energy, we can use the conservation of energy to find the kinetic energy:
Total energy = Potential energy + Kinetic energy
Kinetic energy = Total energy - Potential energy
Kinetic energy = 300 J - 40 J = 260 J
However, we need to know the mass of the object to convert the kinetic energy to velocity. We can use the potential energy to find the mass:
Potential energy = mgh
40 J = m(9.81 m/s^2)(300 m)
m = 0.137 kg
Now we can use the kinetic energy to find the velocity:
Kinetic energy = (1/2)mv^2
260 J = (1/2)(0.137 kg)v^2
v^2 = (2*260 J) / 0.137 kg
v = 43.3 m/s (rounded to one decimal place)
Therefore, the kinetic energy is 260 J and the velocity of the object when it reaches the ground is 43.3 m/s.