Answer:
50
Explanation:
The mechanical advantage of a machine is given by

where
is the output force
is the input force
For the crowbar in this problem,
is the force in input applied by the worker
is the force that the machine must apply in output to overcome the resistance of the window and to open it
Substituting into the equation, we find

Answer:
649kg/m^3
Explanation:
Let p be the density of this particular object.
Formula for density:

We can substitute the givenmass and volume to find density of the object.

Therefore the density of this object is 649kg/m^3.
The velocity of the submarine immediately after firing the missile is 0.0104 m/s
Explanation:
Mass of the submarine M=50 tonne=
Mass of the missile m=40 kg
velocity of the missile v= 13m/s
we have to calculate the velocity of the submarine after firing
This is the recoil velocity and its expression is derived from the law of conservation of momentum
recoil velocity of the submarine

According to Newton's Second Law of Motion :
The Force acting on an Object is equal to Product of Mass of the Object and Acceleration produced due to the Force.
Force acting = Mass of the Object × Acceleration
Given : Force = 50 newton and Mass of the Object = 10 kg
Substituting the respective values in the Formula, we get :
50 N = 10 kg × Acceleration

Acceleration of the Object = 5 m/s²