What is the mechanical efficiency of the lifting system and motor if.?

An electric motor rated at 100w is used to raise a mass of 50kg through 5m in 50 secs.

Could you also show a method for how to work this out please?
Thanks

Answers:
Put simply, efficiency equals the power you receive divided by the power you put in. You'll need these 4 basic equations.
Power = work / time
Work = Force * distance
Force = Mass * acceleration
Efficiency = Output/Input (in %)

The motor is rated at 100w, so that is the power you put in.
To lift 50kg, you need to overcome gravity. In this case, Mass = 50kg, gravitational acceleration = 9.81 m/s.
From here you can calculate the force required. Then you can calculate the work done, and then the power. This is the power you receive. From here, you can calculate the efficiency.

Try to work it out on your own. You'll learn more.
It is in this way:
work done raising the load m*g*h = 50*9.81*5 (joules)
power = p= m*g*h/50 (watts)
entonces calcula si la potencia de 100 w es suficiente o tienes demas.
Sorry for the Spanish, but my ancestors were Spanish, I like this language, and I practice every time.
Power rqd = Energy/time = mgS/t = 9.81*5*50/50 = 49.05Watts

Efficiency = actual power/rated power = 49.05/100 = 49.05%

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