A brick weighing 4.0 kg is dropped into a 1.0 m deep river from a height of 2.0 m. Assuming that 80% of the gravitational potential energy is finally converted into thermal energy, find this thermal energy in calorie.
given:
mass=4kg
height=3m
Formula used:
Potential energi=mgh
M=mass
g=9.8m/s
h=height
so
potential energy=4×10× 3=120J
energi converted to thermal energy=0.8× 120=96J
thermal energi in calories=96/4.2=22.8 cal