The Student Room Group

alevel mechanics question :)

hello hope everyone is doing well! i have a problem with this question since im very confused as to why i got the answer wrong and i don’t really understand the working out attached. can someone please explain to me why my answer isn’t correct, im confused..
https://imgur.com/gbCLNWy
https://imgur.com/Pp4PHPv
Reply 1
Original post by luvkittis
hello hope everyone is doing well! i have a problem with this question since im very confused as to why i got the answer wrong and i don’t really understand the working out attached. can someone please explain to me why my answer isn’t correct, im confused..
https://imgur.com/gbCLNWy
https://imgur.com/Pp4PHPv

Distance travelled is not the same as displacement when the direction of motion changes.
Original post by mqb2766
Distance travelled is not the same as displacement when the direction of motion changes.

thank you so much! would this mean that you would have to find the v value first to see if the direction of motion changes and then find the total distance?
Reply 3
Original post by luvkittis
thank you so much! would this mean that you would have to find the v value first to see if the direction of motion changes and then find the total distance?

Sort of, its fairly easy to reason that the direction of motion will change (upwards/downwards) when v=0 after about 1.5s (as u=14 and g~-10), so it should just be a couple of simple suvats based on that.
(edited 5 months ago)
Original post by mqb2766
Sort of, its fairly easy to reason that the direction of motion will change (upwards/downwards) when v=0 after about 1.5s (as u=14 and g~-10), so it should just be a couple of simple suvats based on that.

alright i get it now. thank you so much for your help :smile:)

Quick Reply