No prefix: How far does a car move before running out of gas on a road?

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A car traveling at 45 km/hr runs out of gas and takes 6.0 seconds to stop. The initial attempt to calculate the stopping distance using the equation x=(vi+vf)/2 * t resulted in an incorrect answer of 135 meters. The correct approach requires converting the initial velocity from kilometers per hour to meters per second, which leads to the accurate distance of 37.5 meters. After making the conversion, the correct answer was confirmed. Proper unit conversion is essential for accurate physics calculations.
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Homework Statement


A car is moving down a road at 45 km/hr when it runs out of gas. How far does the car move if it takes 6.0s to roll to a stop?

Homework Equations


x=(vi+vf)/2 *t I tried this equation, but I got the answer of 135 m. It says the answer is 37.5 m in the answers given by the teacher.

The Attempt at a Solution



I set it up this way:

vi: 45 km/hr
vf: 0
t= 6.0 s
x=?
x= (45+0)/2 * 6.0 = 135 mI want to know what I'm doing wrong, am I using the wrong equation? Thanks.
 
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ArcherofScience said:

Homework Statement


A car is moving down a road at 45 km/hr when it runs out of gas. How far does the car move if it takes 6.0s to roll to a stop?


Homework Equations


x=(vi+vf)/2 *t I tried this equation, but I got the answer of 135 m. It says the answer is 37.5 m in the answers given by the teacher.

The Attempt at a Solution



I set it up this way:

vi: 45 km/hr
vf: 0
t= 6.0 s
x=?
x= (45+0)/2 * 6.0 = 135 m

I want to know what I'm doing wrong, am I using the wrong equation? Thanks.
I suspect that you need to convert the velocity to m/sec.
 


yeh it worked, i got the right answer ! :approve: :D

thankyou! :)
 
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