v²=u²+2as equations of motion question?
I have some physics questions and i missed the last class so missed how to do this... please help and can you show working so i can learn as well...
1)
s=0.07 m
u=48 m/s
v=0
i) t=?
ii) a=?
2)
u=0 m/s
v=24 m/s
a=0.06 m/s
i) t=?
ii) s=?
thank you for your time guys and gals
More Questions From This User See All
Answers & Comments
Verified answer
Equations:
v = u + at
v^2 = u^2 + 2as
s = ut + 0.5at^2
s = vt - 0.5at^2
s = t(u + v) / 2
If you have three pieces of information, you can find the other two by using these five equations. I highly recommend learning them, it's not that hard and it will save you a lot of time in homework and exams.
1) You have s, u and v, so the equations you'll need are:
s = t(v + v) / 2
v^2 = u^2 + 2as
Just plug the numbers in and let the answer fall out:
s = t(u + v) / 2
0.07 = t(48 + 0) / 2
0.14 = 48t
t = 0.14 / 48
t = 0.00291666...
t = 0.0029 s to two significant figures.
v^2 = u^2 + 2as
0 = 48^2 + 2*a*0.07
0 = 2304 + 0.14a
0.14a = -2304
a = -2304 / 0.14
a = 16457.142857...
a = -16000 m/s^2 to two significant figures.
Follow the same procedure for the second question:
v = u + at
24 = 0 + 0.06t
t = 24 / 0.06
t = 400 s
v^2 = u^2 + 2as
24^2 = 0 + 2*0.06*s
576 = 0.12s
s = 576 / 0.12
s = 4800 m
alt..
1)ave v=24m/s..t=s/v=0.07/24=0.0029sec
acceln=(delta)v/t=-48/0.0029= -16457m/s/s
2)acceln=(fin vel-0)/t..>t=24/.06=400sec
S=ave vel*t=12*400=4800m