Answer:
a) 
b) 
c) 
Explanation:
From the question we are told that
Distance to Betelgeuse 
Mass of Rocket 
Total Time in years traveled 
Total energy used by the United States in the year 2000 
Generally the equation of speed of rocket v mathematically given by


where




Therefore


b)
Generally the equation of the energy E required to attain prior speed mathematically given by


c)Generally the equation of the energy
required to accelerate the rocket mathematically given by



1. 12.75 J
Assuming that the force applied is parallel to the ramp, so it is parallel to the displacement of the cart, the work done by the force is

where
F = 15 N is the magnitude of the force
d = 85 cm = 0.85 m is the displacement of the cart
Substituting in the formula, we get

2. 10.6 N
In this part, the cart reaches the same vertical height as in part A. This means that the same work has been done (because the work done is equal to the gain in gravitational potential energy of the object: but if the vertical height reached is the same, then the gain in gravitational potential energy is the same, so the work done must be the same).
Therefore, the work done is

However, in this case the displacement is
d = 120 cm = 1.20 m
Therefore, the magnitude of the force in this case is

Answer
a) Using dimensional analysis we cannot derive the relation, But we can check the correctness of the formula.

now, L H S
s = distance
dimension of distance = [M⁰L¹T⁰]
now, equation on the right hand side
R H S
u = speed
u = m/s
Dimension of speed = [M⁰L¹T⁻¹]
dimension of time
t = sec
Dimension of time = [M⁰L⁰T¹]
Dimension of 'ut' = [M⁰L¹T⁻¹][M⁰L⁰T¹]
= [M⁰L¹T⁰]
now, acceleration= a
a = m /s²
dimension of acceleration = [M⁰L¹T⁻²]
dimension of (at²) = [M⁰L¹T⁻²][M⁰L⁰T¹][M⁰L⁰T¹]
= [M⁰L¹T⁰]
hence, the dimension are balanced.
so, L H S = R H S
b) Moment of inertia of hollow sphere = 
Moment of inertia of solid sphere = 
we know,


Torque is the force that causes rotation
If the same amount of torque is applied to both spheres the sphere with bigger moment of inertia would have smaller angular velocity.
Thus the solid sphere would accelerate more.