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Stuck with SUVAT problem

NaBrO

I've got 2s for (a), got 13.5m for (b) - are these correct?

(edited 3 years ago)

Reply 1

NaBrO

I'm trying to boost the thread to get an answer :bawling:

Reply 2

Hallouminatus

I think your answer to a) is right. Would you like to share your working for b)?

Reply 3

NaBrO

Wait -- do I do:
s = ut + 1/2 at^2
= 14 (2) - 2 (4)
= 20m?

Reply 4

NaBrO

Also does the particle move past the point A, get to a further displacement, turn around and get back to A? i.e. speeding up because now velocity is negative and direction is negative?

Reply 5

Hallouminatus

Original post by NaBrO

Also does the particle move past the point A, get to a further displacement, turn around and get back to A? i.e. speeding up because now velocity is negative and direction is negative?

yes, that's how the particle passes A twice. Part a) asks for the time between those passes, and b) the distance travelled in that time.

Reply 6

NaBrO

Original post by Hallouminatus

yes, that's how the particle passes A twice. Part a) asks for the time between those passes, and b) the distance travelled in that time.

Thank you so so much :rolleyes:

, is my answer to (b) correct?

Reply 7

Hallouminatus

Original post by NaBrO

Thank you so so much :rolleyes:

, is my answer to (b) correct?

Sadly, no. Remember that s is displacement, not distance - what the difference?
Also, u for part b) should be the velocity when P first passes A.

Reply 8

the bear

the particle passes thru A at 2.5 and 4.5 seconds. thus the time when it has v = 0 will be at 3.5 seconds.

you can find the distance travelled between 2.5 and 3.5 seconds and then double it to get the answer to b)