2. Understanding mechanical
advantage and velocity ratio
M.A = Ratio of load to the effort = L/E
V.R = Ratio of distance moved by the effort to
the distance moved by the load
= distance moved by E = x E
distance moved by L x L
Efficiency =M.A/V.R x 100%
= work output x 100%
work input
3. Common simple machines
1. LEVER : Has fulcrum, effort, load.
FIRST ORDER eg claw hammer, crowbar,
pliers
M.A = V.R
4. SECOND ORDER eg nutcracker,
wheelbarrow. L is between F and E.
5. THIRD ORDER E is between L and F. Eg
forearm, Tongs
6. 2 Pulley
In a simple pulley when there is no friction
L = T = E
M.A = 1 = V.R
3 Inclined plane
V.R = x E/x L
= AB/BC = x/h
VR = 1/sinθ
B
CA
hx
θ
