Answer : The kinetic energy of the rock is, 5880 J
Explanation :
Potential energy is defined as the energy possessed due to the height of the object.
Mathematically,
[tex]E_p=mgh[/tex]
where,
[tex]E_p[/tex] = potential energy of the rock at height of 30 m= ?
m = mass of rock = 20 kg
g = acceleration due to gravity = [tex]9.8m/s^2[/tex]
h = height of the bridge from where the rock = 30 m
Putting values in above equation, we get:
[tex]E_p=(20kg)\times (9.8m/s^2)\times (30m)\\\\E_p=5880J[/tex]
According to the law of conservation of mass,
Potential energy = Kinetic energy = 5880 J
Thus, the kinetic energy of the rock is, 5880 J
