A physics problem?

Question

two buddies going to sac town. On a bright sunny day , two friends are on a road trip and drive in two different cars. The two vehicle, Car A and Car B, move along interstate 80 in two different lanes going toward Sacramento.
1.) Car b is 200 m ahead of Car A and is traveling with a constant velocity of 30.0 m/s.
2.) Car A has veloctity 40.0 m/s. The driver observes Car B and applies her brakes, causing a constant acceleration of -0.100 m/s^2. In other words, Car A starts to slow down.
A.) what is the time when Car A passes Car B?
b) what is the time when Car B passes Car A?
c.) what is the velocity of Car A as a function of time?

can u please show which equations u used? plese help

Answer 1

You can envisage the two cars as going the x-direction. Car b is at x=200 and moving at 30m/sec. Car a is a x=0, has been moving at 40 m/sec, and starts a constant deaccleration at that point.

Velocity of car A= 40-0.1 t
Distance of car A = 40t- 0.05 t^2
Distance of car B = 30t + 200.
Set theset two equal to each other and solve. The smaller t will be where A passes B and the larger t will be when B passes A.

Answer 2

S(a)=ut+1/2(a)(t^2)
S(b) = 30t
at t=0, S(a)=0, S(b)=200
when car A passes car B, or car B passes car A, S(a)= S(b)
40t-0.05(t^2)=30t + 200
800t-t^2=600t+4000
t^2-200t+4000=0
The solution for t is answer to both parts

v=u+at
V(a)=30-0.1t

Answer 3

the galaxies rotate at speeds inconsistent with their obvious mass is by technique of the fact we do see all of it. i'm relating it as being the theoretical dark remember. There are very good proofs that shows that dark remember exist. One the is the inconsistent velocity of and obvious mass. dark remember makes up approximately seventy 5% to 80% of the difficulty interior the Universe...