A level maths mechanics help

Hello, Stuck on this question (in the reply)

Reply 1

so I used SUVAT to find the acceleration was -1.66. Then I used the equation v^2 = u^2 + 2as , but this gave two solutions

(edited 10 months ago)

Reply 2

mitostudent

Original post by mitostudent

so I used SUVAT to find the acceleration was -1.66. Then I used the equation v^2 = u^2 + 2as , but this answer was wrong. What mistake have I made?

The actual answer was 4.43, I'm unsure of why the 5.43 was discarded

Reply 3

mqb2766

Original post by mitostudent

The actual answer was 4.43, I'm unsure of why the 5.43 was discarded

If its decelerating, the particle would travel 20 m (t=4.43), then come to rest (v=0) then come back to the same point (t=5.43) but the velocity will be negative. The displacement would be 20 m, but the distance travelled would be greater than that.

Reply 4

Enockkiprop

Original post by mitostudent

Hello, Stuck on this question (in the reply)

Hello, do you still have the questions, I can check it out

Reply 5

davros

Original post by Enockkiprop

Hello, do you still have the questions, I can check it out

The question is in the very first reply, and the explanation has already been provided :smile:

Reply 6

davros

Original post by Enockkiprop

Great! Text me in case of any other similar questions on; REMOVED

Er, any similar problems should be posted in this forum, and TSR doesn't allow contact via personal email addresses so I suggest you remove that!

(edited 10 months ago)

Reply 7

Enockkiprop

Thank you for reminding me this , apologies 🙏

Reply 8

tonyiptony

Original post by davros

Er, any similar problems should be posted in this forum, and TSR doesn't allow contact via personal email addresses so I suggest you remove that! (although the reply function doesn;t seem to let me delete it!0

You can go into the source code (the <\> button) and delete it.

(edited 10 months ago)

Reply 9

davros

Original post by tonyiptony

You can go into the source code (the <\> button) and delete it.

Thanks for that! I took a break from this forum for a while and when I came back the layout had all changed and there seemed to be no end of problems with editing / replying / posting Latex, so I sort of gave up trying to fight it :smile:

Reply 10

mitostudent

Original post by Enockkiprop

Hello, do you still have the questions, I can check it out