The work done by the engine is converted into kinetic energy of the motorbike+rider system:
where
W=6400 J is the work
m=200 kg is the mass of the system
v is the speed acquired by the motorbike
Rearranging the equation and substituting the numbers in, we find
Answer:
K = G Mm / 9R
Explanation:
Expression for escape velocity V_e =
Kinetic energy at the surface = 1/2 m V_e ²
= 1/2 x m x 2GM/R
GMm/R
Potential energy at the surface
= - GMm/R
Total energy = 0
At height 9R ( 8R from the surface )
potential energy
= - G Mm / 9R
Kinetic energy = K
Total energy will be zero according to law of conservation of mechanical energy
so
K - G Mm / 9R = 0
K = G Mm / 9R