- #1
ghostanime2001
- 256
- 0
Homework Statement
A car accelerates at 2.10 m/s2 along a straight road. It passes two marks that are 29.6 m apart at times t=4.10 s and t=4.90 s. What was the car's velocity at t=0?
I'm assuming the car has constant acceleration of 2.10 m/s2
Given
[tex]\Delta[/tex]x = 29.6 m
a = 2.10 m/s2
vi = ?
[tex]\Delta[/tex]t = ? (I was thinking it might be 0.8 s because of 4.9 - 4.1 s )
The equation I think I should use is:
[tex]x_{f} = x_{i} + v_{i}\Delta t + \frac{1}{2}a(\Delta t)^{2}[/tex]
[tex]x_{f} - x_{i}= v_{i}\Delta t + \frac{1}{2}a(\Delta t)^{2}[/tex]
[tex]\Delta x= v_{i}\Delta t + \frac{1}{2}a(\Delta t)^{2}[/tex]
solving for [tex]v_{i}[/tex] gives the expression:
[tex]\frac{\Delta x - \frac{1}{2}a\Delta t^{2}}{\Delta t} = v_{i}[/tex]
substitute all the numbers:
[tex]\frac{(29.6) - \frac{1}{2}(1.2)\(0.8)^{2}}{((0.8)}[/tex]
[tex]36.52 m/s = v_{i}[/tex]
Am I right or wrong with this answer? Also, I couldn't check to make sure if its right or wrong because I kept on thinking the initial velocity should be zero and i held on to that and kept on asnwering that on CAPA and so as a result, I used up all of my tries :(
Last edited: