Answer:
S = 2 π R
R (mean) = 92.9E6 miles
S = 2 * 3.14 * 92.9E6 miles = 5.84E8 miles
The mass of ball a is twice the mass of ball b:

This means that the initial potential energy of ball a (

) is twice the potential energy of ball b (

):

When the two balls reach the ground, the potential energy of each ball has converted into kinetic energy (since now their altitude is h=0), because the total mechanical energy of each ball must be conserved. Therefore:


and so the kinetic energy of ball a must be twice the kinetic energy of ball b:
As the rocket is launched from the ground its height will go on increasing till it stops
So the height of rocket will be maximum when its speed becomes zero
so here we can use energy conservation theory




So it will reach upto height 7.35 m
Answer:
40 MJ (D)
Explanation:
Quantity of heat (Qh) = 100 MJ
temperature of steam (Th) = 450°c = 450 + 273 = 723 K
emperature of water (TI) = 20 °c = 20 + 273 = 293 k
efficiency = (Qh-Qi)/Qh = (Th-Ti)/Th

- Qi= 0.5947 x 
- (0.5947 x
) = Qi
Qi = 40.5 MJ equivalent to 40 MJ (D)