Answer: 112.5N
Explanation: Given that the
Load L = 600N
Distance moved by load = 20cm
Since the lever is one metre, the distance moved by the effort will be
100 cm - 20cm = 80 cm
Efficiency = 75%
Efficiency of a machine is the ratio of the effort multiply by distance covered by the effort to the load multiply by the distance covered by the load as percentage.
75/100 = (effort × 0.8)/ ( 600 × 0.2)
Cross multiply
80 effort = 9000
Effort = 9000/80
Effort = 112.5 N
Therefore, the amount of effort required to lift up the load is 112.5N