AS Maths M1 help - please!

Ok, first of all we start with suvat

s = -10 (if the ball was 10m above the ground, then when it hits the ground it's 10m below it's starting point)
u = u
v = -17.5 (the ball was thrown upwards, so we take that as positive, but comes back down so it'll be negative)
a = -g (again it accelerates downwards)
t = T

So we know v,a and s and want to work out u. What equation do you know that connects all of them together?



And what equation do you know that connects v, a, s and t together?

Need more depth just shout

Thank you, Thank you, Thank you

I've got to u being 10.5 now - I didn't have v as a negative.

This is going to sound stupid, but for part b), when you know v, u, a and s and you want T, how do you know which equation to use?

And for part b, will u be negative or positive?

You can use any equation that contains T and another three values you know

I would pick the one containing v, a and s because u has been rounded to 10.5 so might affect the accuracy of your answer



Basically just pick one direction to be positive (I chose upwards) and then the other direction is negative. As long as you're consistent then it doesn't matter

I've done it!

Could you tell me where I went wrong with question 2?

I did..
u=21
a=-9.8
t=4.5
s= S

so s=ut+1/2xat²
s = 94.5 - 99.225
s = -4.7

I need distance above ground and it is a minus

You haven't made a mistake

s means the displacement of the ball

-4.7 means the ball travelled 4.7m downwards before it hit the ground

That means it was 4.7m above the ground to start with

Hope this makes sense

You can use any equation that contains T and another three values you know
I would pick the one containing v, a and s because u has been rounded to 10.5 so might affect the accuracy of your answer
Basically just pick one direction to be positive (I chose upwards) and then the other direction is negative. As long as you're consistent then it doesn't matter

hi
want i did was i took u as negative as well because i took the point where the displacement of the ball was 0 so i took the situation from there.
U will be negative as it is going down and v as well and the displacement wil lalso be negative with the acceleration also negative.
is this logic correct?

hi
want i did was i took u as negative as well because i took the point where the displacement of the ball was 0 so i took the situation from there.
U will be negative as it is going down and v as well and the displacement wil lalso be negative with the acceleration also negative.
is this logic correct?