An electric motor raises an object of weight 500𝑁 at a uniform speed of 2.0 ms-1...

The current in the electric motor is 10𝐴 at a potential difference of 200𝑉. What is the efficiency of the electric motor?

Hey,

Firstly, we have to understand what this question is asking for, and that is the efficiency for this electric motor in this scenario, more specifically, since the question gives us the requirements to calculate the power output and input of the motor, we will calculate the efficiency in power.

We can use the general equation for efficiency,

We can use the definition of power to calculate the total power input with current (I) and voltage (V)

Since we know the current and voltage of our electric motor, we can find the power,

Next, we can calculate the power output of the motor that contributes to raising the object with work (w) over time (t).

Using the definition of work, which is force (f) times distance (d), we can substitute into the equation,

Next, we know that velocity may be expressed as,

It is given that the velocity of the electric motor raising the object is 2.0 ms−1 and force is 500N,

After finding the total power input and useful power output, we can calculate the efficiency,

I hope this answer helps, please submit more questions if you’re still confused.

Many thanks to an anonymous senior and and an anonymous alumni for inspirations and edits.

Dear Letterbox.

Image source:

• nl.wikipedia.org/wiki/Elektromotor