GCSE Physics Question : Could you please help me with this?

So the first thing you'll want is an equation that relates mass (or weight, but be careful which one you use as they are not the same), change in distance and change in (gravitational) potential energy?

Can you think of such an equation? Maybe your teacher mentioned it in your lessons? We're not really supposed to just do your questions for you.

I am just practicing and I have the answer, but I just don't understand the method. The correct answer is supposedly 1226.25J, but I don't understand why. When I try to work out the answer I times the Mass x Gravitational Field Strength x Height which is 50 x 10 x 2.5 which gives me the answer 1250. I don't know what I am doing wrong to be honest?

Is this the full question? I have an idea what is going on but I would need to see the full question to check.

EDIT: Never mind. Based on your most recent information, they used g = 9.81

Full question is: Achild of 50 kg climbs up a set of stairs and reaches a height of 2.5 m. What isthe child’s gain in potential energy?

???

They have used that the gravitational field strength is 9.81. I had expected them to state what value to use in the question, I could have sworn they did at GCSE but clearly not.

I wasn't given a gravitational field strength of 9.81, I just googled that. The info in the question was the only information I have, and the answer.

Can you explain how you get the answer which was given on my Q Paper?

Sure. The change in gravitational potential energy is given by $mgh = 50 \times 9.81 \times 2.5 = 1226.25 J$

I do not know how you were supposed to know to use g = 9.81. If your teacher has told you to use 10 or 9.8 I would normally stick to that unless the question specifically specifies a value to use (also sometimes it says "use g = ..." on the front of an exam paper, so look out for this).

The key thing is that as long as you are using the equation mgh with a sensible value of g, i.e. 10, 9.8 or 9.81, then you should get all the marks.

Thanks I understand this, what confuses me is that the question asks what is the childs gain in kinetic energy? So I was using the Ek = 1/2(m x v^2) formula, how would I know to use the 'mgh' formula? :s

Can I please see the full question then? The question you originally posted asked only for the increase in GPE when he climbed the stairs.

Sorry sir I wrote the question down incorrectly, it was potential and thanks for before