Hi there, I am a grade 11 student, learning physics.(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

A driver of a car going 90km/h suddenly sees the lights of a barrier 40.0 m ahead. It takes the driver 0.75s before he applies the brakes and the average accelleration during braking is -10.0m/s2.

a) Determine whether or not the car hits tha barrier.

b) What is the maximim speed at which the car could be moving and not hit the barrier at 40.0 m ahead? Assume the accelleration does not change.

a) Treat toward the barrier as positive.

v2=0m/s delta(t)= 40

v1=25m/s

a=-10m/s2

I am not quite sure how to do b)

2. Relevant equations

v2^2 = v1^2 + 2a(delta(d)) <---- a)

3. The attempt at a solution

I have already determined that it would take the car 50 m to come to a complete stop, so it would hit the barrier.

I am having trouble with b)

thanks in advance.

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# Homework Help: Will the car hit the barrier?

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