Explanation:
2. Sum the torques about the fulcrum.
(450 N) (2 m) − (350 N) x = 0
x = 2.57 m
3. Sum the torques about the fulcrum.
(3600 N) (0.20 m) − F (0.90 m) = 0
F = 800 N
Mechanical advantage is the ratio between the load force and effort force.
MA = 3600 N / 800 N
MA = 4.5
Velocity ratio is the mechanical advantage divided by efficiency. Assuming the lever is 100% efficient:
VR = 4.5 / 1
VR = 4.5
4. Mechanical advantage is the ratio between the load force and effort force.
MA = 900 N / 600 N
MA = 1.5
The velocity ratio is the distance moved by the effort divided by the distance moved by the load. For a 3 pulley system, VR = 3.
Efficiency is mechanical advantage divided by velocity ratio.
e = 1.5 / 3
e = 0.50
5. Sum the torques about the fulcrum.
(-300 N) (0.10 m) + F (0.03 m) = 0
F = 1000 N
, while the energy is 
. We can then solve the formula to find V: