Answer:
Distance between centre of Earth and centre of Moon is 3.85 x 10⁸ m
Explanation:
The attractive force experienced by two mass objects is known as Gravitational force.
The gravitational force is determine by the relation:
....(1)
According to the problem,
Mass of Moon, m₁ = 7.35 x 10²² kg
Mass of Earth, m₂ = 5.97 x 10²⁴ kg
Gravitational force experienced by them, F = 1.98 x 10²⁰ N
Universal gravitational constant, G = 6.67 x 10⁻¹¹ Nm²kg⁻²
Substitute these values in equation (1).



d = 3.85 x 10⁸ m
Hooke's Law says that F=-kx where k is the spring constant measured in N/m (newtons per meter)
In a stationary situation, the weight of person is

This is the weight "felt" by the scale, which is basically the normal reaction applied by the scale on the person, and which uses the value of g (9.81) as reference to convert the weight (602.8 N) into a mass (62 kg).
When the person is in the elevator, the scale says 77 kg. The scale is still using the same value of conversion (9.81), so the apparent weight "felt" by the scale is

This is the normal reaction applied by the scale on the person, and which is directed upward. Besides this force, there is still the weight W of the person, acting downward. So, if we use Newton's second law:


where a is the acceleration of the elevator. If we solve for a, we find

The negative sign means the acceleration is in the opposite direction of g (which we take positive), so it means the elevator is going upward.
Answer: E = 941738.537J
Explanation:
to begin,
given that the mass = 2320 pound = 1052.334 kg
Δh = 110 ft = 33.528 m
given that distance (d) = 1283 ft = 391.058 m
also the speed (v) is 65 mph = 29.058 m/s
force (F) = 87 pounds = 386.995 N
from our knowledge in work energy theory;
E = Fd + 1/2mv² + mgh
E = (386.995 × 391.058) + (1/2×1052.334×29.058²) + (1052.334×9.81×33.528)
E = 151337.491 + 444278.2 + 346122.84
E = 941738.537J
i hope this helps, cheers.