Find out load lifted by the machine:
An effort of 400 N is applied in a lifting machine. The distance moved through effort is 4 m and that by load is 40 cm. If the efficiency of the lifting machine is 70%, Find out
1. load lifted by the machine
2. mechanical advantage
3. velocity ratio
Solution
Effort applied (P) = 400 N
Distance moved by effort (y) = 4 m
Distance moved by load (x) = 40 cm = 0.4 m Efficiency of the lifting machine η = 70% or 0.7. (i) Output = Load × distance moved by load
= W × 0.4
Input = 400 × 4 = 1600 Nm
η= Output/ Input , or
= 0.7 = 0.4 W/1600
or, W =( 0.7 × 1600) /0.4 = 2800 N
Ans.
(ii) Mechanical Advantage (M. A.) = W/P
= 2800/400
= 7.0 Ans.
(iii) Velocity Ratio (V. R.) = y/ x = 4 /0.4 = 10 Ans.