A-Level Maths: Q3-09 [SUVAT: More Complicated Problem 1]

[lelouchvibritannia]

wouldnt a be +9.8 because the object is acting towards the force of gravity?

[AlEx-rokd]

damn i've done so many examples but i cant nail itttt

[aisha]

It's been 2 years and I still, literally cannot get the signs the right way round. So if you take UP as positive, then anything falling DOWN will have negative acc/velocity/displacement? <Will these three always have the same sign? When are different signs involved? Thank you so much

[joshuacarpenter]

What's with the structure techniques ;)?

[medicusv]

Hi Sir, please could you help me?

Out of all your videos - this is the only one I found confusing. Mainly due to the contradictions between the value of g in other questions.

In this the ball is moving downwards and so gravity should be positive, right?
In the next video of the playlist, a ball is projected upwards and gravity is negative?

I just thought that if it moves up its negative, down it's positive?


I've looked through the comments you've left but i still don't understand. Sorry to bother you!

[mangelo_]

could we assume that this acceleration is constant and terminal velocity is never reached?

[tahirnaeem]

Hi Jack
Just relating to the Q I asked in the next problem 10.. I understand why you have taken g as negative in this scenario as the stone is being dropped down.. and thus the velocity and displacement will also be negative as it is in downward direction.. but in Q3-10 it was a similar scenario where you are modelling the particle being dropped down and you took g as positive.. sonthats why I am confused and would appreciate further clarification.. thanks. Tahir

[mohammedhasan]

I think you're wrong. 2.5s is the total time for the stone hitting the water and the sound produced traveling back to the top.