They have different accelerations because of their masses. According to Newton's Second Law, an objects acceleration is inversely proportional to its mass. Therefore the object with the larger mass, in this case the gun, will have a smaller acceleration. In the same way, the less massive object, being the bullet, will have a higher acceleration.
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Answer:
a) The strength of gravity decreases if one moved away from Jupiter
b) The strength of gravity increases if one fell into Jupiter
Explanation:
The gravitational attraction is given by Newton law of gravitation as follows;

Where;
G = The universal gravitational constant = 6.67408 × 10⁻¹¹ m³/(kg·s²)
M = The mass of Jupiter
m = The mass of the nearby body
R = The distance between the centers of Jupiter and the body
From the equation, we have that the gravitational strength varies inversely with the square of the separation distance between two bodies
Therefore, as one moves away, R increases, and the strength of gravity reduces
Similarly as the body falls into Jupiter, R, reduces the gravitational strength increases.
Yes, with simple machines
part 1
mass = ρ x V
mass = 1739 kg/m³ x 3.8 km³ = 6608.2 kg
PE (potential energy)= mgh
PE = 6608.2 kg x 9.81 x 403
PE = 2.61 x 10⁷ J
part 2
megaton of TNT (Mt) =4.2 x 10¹⁵ J
convert PE to Mt:
2.61 x 10⁷ J : 4.2 x 10¹⁵ J = 6.21 x 10⁻⁹ Mt
Uhhh I’m not really sure of the answer i think it’s stratosphere