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SteveThePharmer
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Quick "Equations of Motion" questions (2). Rxn time; deceleration
1. A meteorite strikes on October 9, 1992, a 27-pound meteorite struck a car in Peekskill, NY, leaving a dent 22 cm deep in the trunk. If the meteorite struck the car with a speed of 130 m/s, what was the magnitude of its deceleration, assuming it to be constant?
27# meteorite
22cm dent in trucnk
130 m/s
v^2=v0^2+2a(x-x0)=v0^2+2a(change in)x
v=-22
v0=130m/s
a=? (to be solved for)
x=?
x0=?
I'm pretty sure this is not the equation since distance is not given.
I'm lost without the correct equation... :(
1. You are driving through town at 16 m/s when suddenly a car backs out of a driveway in front of you. you apply brakes and begin decelerating at 3.2 m/s^2.
c. If the car backing out was initially 55 m in front of you, what is the maximum reaction time you can have before hitting the brakes and still avoid hitting the car?
v0=16m/s
a=-3.2 m/s^2
(change in)x=55 m
v=0
[(change in)x=v^2-v0^2]/[2a]
v=v0+at=0
0=16m/s+(-3.2m/s^2)t
t=5s?
answer given is 0.945s, but i want to learn how to get there.
Thanks for looking!
Steve
If I could just get an equation, that would help greatly!
Thanks again!
1. A meteorite strikes on October 9, 1992, a 27-pound meteorite struck a car in Peekskill, NY, leaving a dent 22 cm deep in the trunk. If the meteorite struck the car with a speed of 130 m/s, what was the magnitude of its deceleration, assuming it to be constant?
27# meteorite
22cm dent in trucnk
130 m/s
Homework Equations
v^2=v0^2+2a(x-x0)=v0^2+2a(change in)x
v=-22
v0=130m/s
a=? (to be solved for)
x=?
x0=?
I'm pretty sure this is not the equation since distance is not given.
The Attempt at a Solution
I'm lost without the correct equation... :(
1. You are driving through town at 16 m/s when suddenly a car backs out of a driveway in front of you. you apply brakes and begin decelerating at 3.2 m/s^2.
c. If the car backing out was initially 55 m in front of you, what is the maximum reaction time you can have before hitting the brakes and still avoid hitting the car?
v0=16m/s
a=-3.2 m/s^2
(change in)x=55 m
v=0
Homework Equations
[(change in)x=v^2-v0^2]/[2a]
v=v0+at=0
The Attempt at a Solution
0=16m/s+(-3.2m/s^2)t
t=5s?
answer given is 0.945s, but i want to learn how to get there.
Thanks for looking!
Steve
If I could just get an equation, that would help greatly!
Thanks again!