A mechanical device requires 420 J of work to do 230 J of work in lifting a crate. What is the efficiency of the device?

I keep getting 0.5% am I right?

Eff. = (Output/Input)*100% =(230/420)*100 = 54.8%

To find the efficiency of a device, you need to divide the output work by the input work and multiply the result by 100 to convert it to a percentage.

Efficiency = (Output work / Input work) x 100

Given that the input work is 420 J and the output work is 230 J, we can calculate the efficiency as follows:

Efficiency = (230 J / 420 J) x 100
Efficiency = 0.5476 x 100
Efficiency = 54.76%

So, the efficiency of the device is approximately 54.76%, not 0.5%.

To calculate the efficiency of a device, you need to use the formula:

Efficiency = (Useful energy output / Total energy input) * 100

In this case, the useful energy output is the work done in lifting the crate, which is 230 J. The total energy input is the work required to do that useful work, which is given as 420 J.

Now, let's calculate the efficiency using the provided values:

Efficiency = (230 J / 420 J) * 100

Efficiency = (0.5476) * 100

Efficiency = 54.76%

Therefore, the efficiency of the device is 54.76%, not 0.5%.

I am wondering the same thing