Thread: Gravity-Work Question

How much work is done by gravity in causing a 24 kg rock to tumble 50m down a slope at an angle 48 degrees to the verticle, to one decimal place?

Originally Posted by peon123

How much work is done by gravity in causing a 24 kg rock to tumble 50m down a slope at an angle 48 degrees to the verticle, to one decimal place?

I believe it is



(this works for the horizontal angle)



I think that's right, if you have an answer please post it because there could be another way to do it

Originally Posted by peon123

How much work is done by gravity in causing a 24 kg rock to tumble 50m down a slope at an angle 48 degrees to the verticle, to one decimal place?

Work done is equal to , where is the force acting on the particle and is the displacement.

If I remember my mechanics correctly, then as the question is asking you the work done by gravity, it is the horizontal displacement that you are after, which is equal to .

Then as we are interested in the direction of gravity, would it be ?

This works out to be or .

Just to note, I have taken as 9.8, as opposed to 9.81.

Just realised that we used the same equations

Originally Posted by e^(i*pi)

There's a typo in your answer, it should be , not

Originally Posted by craig

Just realised that we used the same equations



There's a typo in your answer, it should be , not

Yeah, I checked that on my calculator, makes sense since

Thanks for that, I worked it out in kJ first but had to expand for the 1dp