Can someone help me with this Physics problem. A boy sledding down a hill accelerates at 2.15 m/s2. If he started from rest, in what distance would he reach a speed of 5.70 m/s? My teacher gave me these equations to use with it. Which one should I use?

vf = at + vi
x = 1/2(vf + vi)t
x = 1/2at^2 + vit
vf^2 = vi^2 + 2ax

Question

Can someone help me with this Physics problem.  A boy sledding down a hill accelerates at 2.15 m/s2. If he started from rest, in what distance would he reach a speed of 5.70 m/s?  My teacher gave me these equations to use with it.  Which one should I use?

vf = at + vi 
x = 1/2(vf + vi)t 
x = 1/2at^2 + vit 
vf^2 = vi^2 + 2ax

anonymous · Answer

look at your given information. you have vi=0 vf=5.7 a=2.15 and you are looking for x. so use the 4th one

anonymous · Answer

thank you!!