Answer:
58.7g (answer might differ a little if the answer treats g as 10 instead of 9.81ms-2)
Step-by-step explanation:
First, apply the formula Energy = Power x Time
Power -> 480W (given)
Time -> 12 seconds (given)
Hence,
Energy = (480 x 12) J (SI units of energy is in Joules, J)
= 5760 J
Since Sarita lifts up the mass, the energy we have calculated above is gravitational potential energy.
That means 5760 J of gravitational potential energy.
Recall that another formula for gravitational potential energy (GPE) is
GPE = mgh (where h is the height lifted, mass is the mass and g is the gravitational constant of 9.81ms-2)
h = 10 metres (given)
Therefore,
5760 = m x 9.81 x 10
98.1m = 5760
m = 58.71559g
Hence, mass lifted is 58.7g (in 3sf)