Answer:
1250 N
Explanation:
length of wrench = 20 cm = 0.2 m
Write the length of wrench in vector form
r = 0.2 j metre
Direction of force= 
Let the magnitude of force is F
So, write the force in vector form
F = F
torque, T = 150 Nm
Torque = T = r x F
F = 1250 N
Thus, the magnitude of force is 1250 N.
Answer:
The Elevator
Explanation:
The frame of reference is the immovable item and remains at the same place and can be used for guiding some one. For example I am telling you an address by saying that you will cross the mega store and then there will a Ferrari and on the next street is my home. So you kept searching my home and then you called me again. I checked from my window before receiving call and saw that the ferrari was gone. So it took more time which means that the frame of reference choosen was movable item. The frame of reference choosen is always immovable. So here I want to move towards elevator which is immovable so choosed it. Furthermore, ship is movable item and the ocean doesn't specify right direction thatswhy stars were used in the ancient times.
Answer:
25 m/s in the opposite direction with the ship recoil velocity.
Explanation:
Assume the ship recoil velocity and velocity of the cannon ball aligns. By the law of momentum conservation, the momentum is conserved before and after the shooting. Before the shooting, the total momentum is 0 due to system is at rest. Therefore, the total momentum after the shooting must also be 0:
where 
are masses of the ship and ball respectively. 
are the velocities of the ship and ball respectively, after the shooting.
So the cannon ball has a velocity of 25 m/s in the opposite direction with the ship recoil velocity.
