Answer:
2.1844 m/s
Explanation:
The principle of conservation of momentum can be applied here.
when two objects interact, the total momentum remains the same provided no external forces are acting.
Consider the whole system , gun and bullet. as an isolated system, so the net momentum is constant. In particular before firing the gun, the net momentum is zero. The conservation of momentum,

assume the bullet goes to right side and the gravitational acceleration =10 
so now the weight of the rifle=

this is a negative velocity to the right side. that means the rifle recoils to the left side
Work needed = 23,520 J
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Further explanation
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Given
height = 12 m
mass = 200 kg
Required
work needed by the crane
Solution
Work is the transfer of energy caused by the force acting on a moving object
Work is the product of force with the displacement of objects.
Can be formulated
W = F x d
W = Work, J, Nm
F = Force, N
d = distance, m
F = m x g
Input the value :
W = mgd
W = 200 kg x 9.8 m/s²x12 m
W = 23520 J
Answer:
Mechanical advantage = 15
Explanation:
Given the following data;
Output force = 3000N
Input force = 200N
To find the mechanical advantage;
Mechanical advantage = output force/input force
Substituting into the equation, we have
Mechanical advantage = 3000/200
Mechanical advantage = 15
1,000 milligrams = 1 gram
2,000 milligrams = 2 grams
3,000 milligrams = 3 grams
4,000 milligrams = 4 grams
Answer;
1. strong nuclear force
2. electromagnetic force/ electric force
Explanation;
The more protons an element has, the harder it is to bring nuclei together. It takes more energy to trigger fusion in iron and other heavy elements. Lighter elements, such as helium and hydrogen, require less energy to bring about fusion. The sun, for instance, spends most of its life converting hydrogen into helium.
-The strong nuclear force depends on; a more massive the object is the more attractive the force produced and also as distance between objects increases, attractive force decreases at a faster rate.