a car travels at 3m/s but is accelerating constantly at 2/3 m/s. A bike is traveling at 5m/s. Find the point at which the car has travelled twice as far from the start as the bike. Thanks :)

Question

anonymous · Answer

your welcome :D

katielong · Answer

would you be able to help out?

anonymous · Answer

That depends if you are ready to help yourself ;-)

alright.. i believe you need to calculate the time? right?

katielong · Answer

yeah

anonymous · Answer

soo.. 
yo uunderstnd that problem?!

katielong · Answer

yeh?

anonymous · Answer

so then.. can you start ..? i ll help you if you get stuck!

katielong · Answer

i dont know how to start though

anonymous · Answer

well.. imagine that the biker boy travels X distance in time t

then in the same time how much distance should the car travel?

katielong · Answer

2x

anonymous · Answer

ok.. 
so .. now set up equations

biker boy traveling at 5m/s, he travels x meters in t sconds. waht equation can u set up?!

katielong · Answer

5=x/t

anonymous · Answer

good
now lets go to the car

car starts with 3m/s.. accelerates at 2/3 m/s^2 . travels a distance 2x in time t.. what equation can u set up?!

katielong · Answer

ummm.... 2/3=3/t ???

anonymous · Answer

do you think thats right? :P

anonymous · Answer

madam.. acceleration is NOTTTT equal to velocity over time.. this is like some sort of misconception students have :-/

acceleration is CHANGE IN VELOCITY over time.. it tells you how much a velocity is changing over time


imagine if i said velocity  = position /time.. does that make sense ?? no right??

velocity  = CHANGE in position / time!! get it?!?

katielong · Answer

ohhh okay

anonymous · Answer

so for that reason.. we have 3 equations of motion .. to deal with accelerated motions..

anonymous · Answer

ll be back in 10 ok?

katielong · Answer

but what do i do from here then? in short?

anonymous · Answer

use equation of motion to set up an equation?

katielong · Answer

equation of motion?

katielong · Answer

what do you mean?

anonymous · Answer

3 equations of motion?! haven't you dealt with accelerated motions before?

anonymous · Answer

equations which connect, displacement, initial velocity, final velocity, time acceleration?

katielong · Answer

oh 'suvat' equations: 
v=u+at
s=1/2(u+v)t
v^2=u^2 + 2as

katielong · Answer

i'm not on the topic with those yet thought so they shouldn't be nessecary

katielong · Answer

any tips?

katielong · Answer

done it.