Calculate Work, Power, PE and KE for a 400W Motor

[Googl]

I have a question where I am given watts, voltage and time. Let's say the electric motor is 400 watt that is run from 240v mains electricity for 200seconds.

I have managed to calculate the work done using the formula Work done (J) = Power (W) x time taken (J) And I have managed to calculate the current the motor uses using the formula Power = IV.

I have no idea how I would calculate how long it takes for the pulley system to raise 15kg mass vertically 5 metres when the motor is connected to the pulley.

I am also asked to calculate the PE of the fully raised mass, I assume here I would use this formula;

Potential= mgh (Am I right?)

How do I calculate it's velocity after falling for 3.5 metres? Do I use this formula? KE= 1/2 MV^2

Thanks.

 

[edgepflow]

The motor's power is given. As you mentioned, Energy = Power X Time and Potential Energy = m g h.

 

[Googl]

The motor's power is given. As you mentioned, Energy = Power X Time and Potential Energy = m g h.

I figured how to work out but the others.

 

[Naty1]

How do I calculate it's velocity after falling for 3.5 metres?

d = v₀t + 1/2at²

 

[edgepflow]

The total Energy is constant: KE + PE = constant. If one goes down, the other goes up.

 

[Googl]

How do I calculate it's velocity after falling for 3.5 metres?

d = v₀t + 1/2at²

But if I rearrange the formula (making v₀ the subject) it will only give me the original velocity and not the velocity is is at after 3.5 metres. Are saying that after finding this I should use; v^2 = u^2 + 2as to find the velocity at 3.5 metres?

how I would calculate how long it takes for the pulley system to raise 15kg mass vertically 5 metres when the motor is connected to the pulley.

 

[Googl]

Hi, Could someone please help me out.