Work done climbing a flight of stairs.

[fattydq]

A 58 kg firefighter climbs a flight of stairs 5.3 m high. How much work is required?

I know work is just force times distance, but I'm not given a force? And I can't really find a force because force is mass times acceleration and I'm not given an acceleration...help!

 

[mgb_phys]

Do you know about gravitational potential energy?

Actually you are given a force, if he has a mass of 58kg (you must have some skinny firemen!) and he is on Earth, how much does he weigh?

 

[fattydq]

Do you know about gravitational potential energy?

Actually you are given a force, if he has a mass of 58kg (you must have some skinny firemen!) and he is on Earth, how much does he weigh?

9.8 times 58...so 568.4 N right? Then 568.4 times 5.3m and you get 3012.52, yes? Would the unit be joules?

 

[mgb_phys]

Yes - but think about how many significant figures you should have

The equation for potential energy = m g h
As you said this is the same as force (mg) * distance (h)
And yes J = N m = kg m^2/s^2

 

[fattydq]

Would it just be 3.0 times 10^3 in correct sig figs?

 

[fattydq]

?

 

[mgb_phys]

Yes, you have 2 sig figures for the mass and height so it's two sig figures for the answer.
So formally 3.0 x 10^3 J or 3000J would probably be ok.