Because of gravity and friction.
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.
Hope this helps :)
Answer:


Explanation:
As the disc is unrolling from the thread then at any moment of the time
We have force equation as

also by torque equation we can say



Now we have



Also from above equation the tension force in the string is


Using the equation P = W/t to solve your problem .
Thus the answer is all of them use the same amount of power. 20 J.
Answer:
The mass of the object is 49.5kg which is approximately 50kg
Explanation:
Given that
Spring constant (k)=45N/m
The extension (e)=0.88m
Also given that the acceleration is 0.8m/s²
Force by the spring is given as
Using hooke's law
According to Hooke's law which states that the extension of an elastic material is directly proportional to the applied force provided that the elastic limit is not exceeded. Mathematically,
F = ke where
F is the applied force
k is the spring constant
e is the extension
From the formula k = F/e
F=ke
m is the mass of the block = ?
a is the acceleration = 0.8m/s²
e is the extension of the spring = 0.88m
k is the spring constant = 45N/m
F=45×0.88
F=39.6N
Now this force will set the object in motion, now using newton second law of motion
F=ma
Then, m=F/a
m=39.6/0.8
m=49.5kg
The mass of the object is 49.5kg which is approximately 50kg