Answer :
At 20 m kinetic energy is 0 J, Potential energy is 392.4 J and total energy is 392.4 J
At 10 m kinetic energy is 196 J, Potential energy is 196.2 J and total energy is 392.4 J
At 0 m kinetic energy is 392.4 J, Potential energy is 0 J and total energy is 392.4 J
Explanation:
Kinetic energy = 0.5 x Mass x Velocity²
KE = 0.5mv²
Potential energy = Mass x Acceleration due to gravity x Height
PE=mgh
Here m = 2 kg
g = 9.81 m/s²
Substituting
KE = 0.5 x 2 x v² = v²
PE= 2 x 9.81 x h = 19.62h
At height 20 m:-
v = 0 m/s
h = 20 m
Substituting
KE = v² = 0² = 0J
PE= 19.62 x 20 = 392.4 J
Total energy = 0 + 392.4 = 392.4 J
At 20 m kinetic energy is 0 J, Potential energy is 392.4 J and total energy is 392.4 J
At height 10 m:-
We have equation of motion v²=u²+2as
v = ?
u = 0 m/s
s = 20 - 10 = 10 m
a = 9.81 m/s²
v²=0²+2 x 9.81 x 10
v = 14 m/s
v = 14 m/s
h = 10 m
Substituting
KE = v² = 14² = 196 J
PE= 19.62 x 10 = 196.2 J
Total energy = 196 + 196.2 = 392.4 J
At 10 m kinetic energy is 196 J, Potential energy is 196.2 J and total energy is 392.4 J
At height 0 m:-
We have equation of motion v²=u²+2as
v = ?
u = 0 m/s
s = 20 - 0 = 20 m
a = 9.81 m/s²
v²=0²+2 x 9.81 x 20
v = 19.81 m/s
v = 19.81 m/s
h = 0 m
Substituting
KE = v² = 19.81² = 392.4 J
PE= 19.62 x 0 = 0 J
Total energy = 392.4 + 0 = 392.4 J
At 0 m kinetic energy is 392.4 J, Potential energy is 0 J and total energy is 392.4 J