# Kinematic Equations Problem: Toy cars on adjacent tracks

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1. Feb 1, 2017

### dsfrankl

1. The problem statement, all variables and given/known data
At t = 0, one toy car is set rolling on a straight track with initial position 16.0 cm, initial velocity -3.7 cm/s, and constant acceleration 2.90 cm/s2. At the same moment, another toy car is set rolling on an adjacent track with initial position 10.0 cm, an initial velocity of 4.90 cm/s, and constant zero acceleration.

(a) At what time, if any, do the two cars have equal speeds?
(b) What are their speeds at that time?
(c) At what time(s), if any, do the cars pass each other? (If there is only one time, enter NA in the second blank. If there are two times, enter the smaller time first.)
(d) What are their locations at that time? (If there is only one position, enter NA in the second blank. If there are two positions, enter the smaller position first.)
(e) Explain the difference between question (a) and question (c) as clearly as possible. Write for a target audience of students who do not immediately understand the conditions are different.

2. Relevant equations
Kinematic equations:

Vf=Vi+at
Δx=Vit+1/2at^2
Vf^2=Vi^2+2aΔx
Δx=1/2(Vf+Vi)t

3. The attempt at a solution
(a) t = 2.97s
(b) v = 4.9cm/s
(c) ???
(d) ???
(e) ???

2. Feb 1, 2017

### Staff: Mentor

Hi @dsfrankl, Welcome to Physics Forums.

You'll need to show details about what you've tried. You've given our helpers nothing to work with, and they can't help until you've shown that work.

3. Feb 1, 2017

### BvU

Hello dsf,

I suppose the question you want to ask is "???"
My question is: how can you calculate (a) with the relevant equations you are listing ?

PF guidelines require you make a start yourself. Is it clear what you are being asked ? in (c) and (d) ?