Car moving down road

  • #1
ArcherofScience
36
2
car moving down road...

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.
 

Answers and Replies

  • #2
SammyS
Staff Emeritus
Science Advisor
Homework Helper
Gold Member
11,647
1,223


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.
 
  • #3
ArcherofScience
36
2


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

thankyou! :)
 

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