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.