Kinematic Equations Problem: Toy cars on adjacent tracks

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SUMMARY

The discussion focuses on solving kinematic equations for two toy cars on adjacent tracks. The first car starts at 16.0 cm with an initial velocity of -3.7 cm/s and a constant acceleration of 2.90 cm/s², while the second car starts at 10.0 cm with an initial velocity of 4.90 cm/s and zero acceleration. The key findings include that the two cars have equal speeds at approximately 2.97 seconds, with a speed of 4.9 cm/s at that time. Further calculations are needed to determine when the cars pass each other and their respective positions at that time.

PREREQUISITES
  • Understanding of kinematic equations, specifically Vf=Vi+at and Δx=Vit+1/2at².
  • Knowledge of initial conditions in motion problems, including initial position and velocity.
  • Ability to solve quadratic equations to find time and position.
  • Familiarity with the concept of acceleration and its impact on velocity.
NEXT STEPS
  • Calculate the time when the two toy cars pass each other using the equation Δx=Vit+1/2at².
  • Determine the positions of both cars at the time they pass each other.
  • Explore the differences between equal speeds and passing positions in kinematic problems.
  • Review additional kinematic equations such as Vf²=Vi²+2aΔx for further insights.
USEFUL FOR

This discussion is beneficial for students studying physics, particularly those learning about kinematic equations and motion analysis. It is especially relevant for those tackling homework problems involving multiple objects in motion.

dsfrankl
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Homework Statement


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.

Homework Equations


Kinematic equations:

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

The Attempt at a Solution


(a) t = 2.97s
(b) v = 4.9cm/s
(c) ?
(d) ?
(e) ?[/B]
 
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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.
 
Hello dsf, :welcome:

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

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

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