What is the amount of effort required to lift up 600N load by using a lever of one meter length whose fulcrum is 20cm far from load? Efficiency=75%

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

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000