More Physics

posted by .

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 -

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 -

... we havn't even learned about Kinetic energy yet... my teacher must be losing it.... haha

• More Physics -

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

Similar Questions

1. physics

A car of mass 1330 kg is traveling at 28.0 m/s. The driver applies the brakes to bring the car to rest over a distance of 79.0 m. Calculate the retarding force acting on the car. (79.0/28.0)*1330 3752.5 I asked before but I wasn't …
2. physics repost

A car of mass 1330 kg is traveling at 28.0 m/s. The driver applies the brakes to bring the car to rest over a distance of 79.0 m. Calculate the retarding force acting on the car. same as before just posting again so you wont have to …
3. Physics

A car mass of 1330 kg is traveling at 28.0 m/s. The driver applies the brakes to bring the car to a rest over a distance of 79.0 m. Calculate the retarding force.
4. Physics

A 1000-kg car is driving toward the north along a straight road at a speed of 20.0 m/s. The driver applies the brakes and the car comes to a rest in a distance of 140 m. What is the constant force applied to the car to bring it to …
5. Physics

A car of mass 1550 kg is travelling at 75.0 km/h on a dry horizontal concrete surface when the driver applies the brakes licking the wheels. (a) How far does the car travel before coming to rest?
6. Physics HELP!

I have NO idea how to do this! any help is great! A car of maass 1330kg is traveling at 28m/s. The driverapplies the brakes to bring the car to a rest over a distance of 79m. Calculate the retarding force acting on the car. From this …
7. Physics

Problem 4- Speedy car, driving at 30 m/s. The driver suddenly observes a slow-moving van 155 m ahead traveling at 5 m/s in the same direction. The driver of the car immediately applies the brakes causing a constant acceleration of …
8. calculus

The driver of a car traveling at 60 ft/sec suddenly applies the brakes. The position of the car is s(t) = 50t - 2t2, t seconds after the driver applies the brakes. How many seconds after the driver applies the brakes does the car come …
9. physics

The driver of a car traveling at 60 ft/sec suddenly applies the brakes. The position of the car is s(t) = 50t - 2t2, t seconds after the driver applies the brakes. How many seconds after the driver applies the brakes does the car come …
10. math, physics

The driver of a car traveling at 60 ft/sec suddenly applies the brakes. The position of the car is s(t) equals 60t minus - 1.5t^2, t seconds after the driver applies the brakes. How many seconds after the driver applies the brakes …

More Similar Questions