Posted by Maggie on Wednesday, December 5, 2012 at 7:40pm.
I have NO idea how to do this! any help is great!
A car with a mass of 1330kg is traveling at 28m/s. The driver applies the brakes to bring the car to a rest over a distance of 79m. Calculate the retarding force acting on the car.
From this i can see that it gives me the
Mass:1330kg
the inicial velocity: 28m/s
and the distance: 79m
i'm trying to find the force, but i can't think of a formula using the known variables!!

Physics  eintstein, Wednesday, December 5, 2012 at 7:56pm
you can find the force doen through W=Fd, where W is work done,F is force applied, and D is the displacement(79m)
Work done also equlals change in kinetic energy, which is 521360J, sp the force applied is 6599.5 N.

Physics  Maggie, Wednesday, December 5, 2012 at 8:04pm
... we havn't even learned about Kinetic energy yet... my teacher must be losing it.... haha

More Physics  naomi, Wednesday, December 5, 2012 at 8:48pm
You have to use three formulas for this one, I'm afraid.
First you need to find out how long it takes for the car to decelerate during those 79m.
Then you have to figure the acceleration, knowing the speed and the time.
And finally you have to translate that acceleration into a force.
For the first part you'll need this formula (to find out the time taken to stop):
Distance = (Final Speed + Initial Speed ) x Time/2
79 = 28 x T/2
T = 5.64s
For the second step, you have the following formula (to find the acceleration):
Final Speed = Initial Speed  Acceleration x Time
0 = 28  A x 5.64
A = 4.96m/s^2
Finally, you have the force formula:
Force = Mass x Acceleration
F = 1330 x 4.96
Force = 6596.8N
Answer This Question
Related Questions
 Physics HELP!  I have NO idea how to do this! any help is great! A car of maass...
 Physics  A car mass of 1330 kg is traveling at 28.0 m/s. The driver applies the...
 physics  A car of mass 1330 kg is traveling at 28.0 m/s. The driver applies the...
 physics repost  A car of mass 1330 kg is traveling at 28.0 m/s. The driver ...
 Physics  A 1000kg car is driving toward the north along a straight road at a ...
 Physics  A 1000kg car is driving toward the north along a straight horizontal ...
 math, physics  The driver of a car traveling at 60 ft/sec suddenly applies the ...
 Physics  The driver of a 1350 kg car, initially traveling at 10.6 m/s, applies ...
 physics  The driver of a car traveling at 60 ft/sec suddenly applies the brakes...
 Physics  Problem 4 Speedy car, driving at 30 m/s. The driver suddenly observes...
More Related Questions