- #1
monkfishkev
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Suvat -- Two cars approach each other on a straight road
Two cars approach each other on a straight road. Car A is moving at 16m/s and car B at 8m/s. When they are 45m apart both drivers apply their brakes. Car A slows down at a rate of 2m/s^2 while car B slows down at 4m/s^2. Where and when do the cars collide?
I'm assuming that this would result in a simultaneous equation given that there are two unknowns; distance (s) and time (t) (where and when).
CAR A
s = s
u = 16m/s
v = x
a = -2m/s^2
t = t
s = ut + 1/2 at^2
s = 16t - t^2
Equation 1
CAR B
s = s
u = 8m/s
v = x
a = -4m/s^2
t = t
s = ut + 1/2 at^2
s = 8t - 2t^2
Equation 2
Equation 1: s = 16t - t^2
Equation 2: 2s = 16t - 4t^2
It is at this point I fall as I still land up with two unknown variables: -s = 5t^2
Where am I going wrong?
Homework Statement
Two cars approach each other on a straight road. Car A is moving at 16m/s and car B at 8m/s. When they are 45m apart both drivers apply their brakes. Car A slows down at a rate of 2m/s^2 while car B slows down at 4m/s^2. Where and when do the cars collide?
Homework Equations
I'm assuming that this would result in a simultaneous equation given that there are two unknowns; distance (s) and time (t) (where and when).
The Attempt at a Solution
CAR A
s = s
u = 16m/s
v = x
a = -2m/s^2
t = t
s = ut + 1/2 at^2
s = 16t - t^2
Equation 1
CAR B
s = s
u = 8m/s
v = x
a = -4m/s^2
t = t
s = ut + 1/2 at^2
s = 8t - 2t^2
Equation 2
Equation 1: s = 16t - t^2
Equation 2: 2s = 16t - 4t^2
It is at this point I fall as I still land up with two unknown variables: -s = 5t^2
Where am I going wrong?