Help with this question..please?

Question

car A is traveling north at 30 m/s and car B is traveling south at 20 m/s. if both cars have a southward acceleration of 1 m/s2, comapre their speeds after 1 second

um..
easy way. im only in 7th grade. =/
=/

Answer 1

car A
vf=vi+at
vf=30+(-1)(1)
vf=29m/s north
car B
vf=20+(1)(1)
vf=21m/s south
car A/car B=29/21

Answer 2

now, car A is traveling north but it acceleration is southward. this mean car A is decelerating. while car B is accelerating.

since the information given in the question is only acceleration, initial velocity of each car, and time. just use the equation v = u + at where,
v=final velocity
u=initial velocity
a=accleration
t=time

for car A, the final velocity, v(A) = 30 + (-1)(1)
for car B, the final velocity, v(B) = 20 + (1)(1)
compare them, v(A)/v(B) = 1.5 meaning after 1 second, car A still going 1.5 factor faster than car B.

Answer 3

Think what acceleration means. 1 m/s^2 means the speed changes by 1 m/s every second. So it goes 20,21,22. or 20,19,18, depending on whether the acceleration is in the same direction as the speed or opposite.
I'm sure someone will tell you the actual answer, but with this hint, you should be able to figure it out, so you can it yourself all the time in the future.

Answer 4

v(t) = v0 + at

assume north is positive

for carA we are given v0=30, a=-1, so v(1)=30-1*1=29m/s
for carB we are given v0=-20, a=-1, so v(1)=-20-1*1=-21m/s, or 21m/s south