A 1200 kg car going 30 m/s skids to a rest.

Question

The friction force is 6000 N. How far does it skid?

Answer 1

 

Hey again, Sierra -- braking decel is 6000N/1200kg = 5 m/s/s taking 6 secs to stop ...

ave speed of 15m/s moving for 6 sec travels 90m ... Regards :)

Answer 2

Because the car completely stops you can apply the standard formula connecting the acceleration, distance traveled, initial and final speed. Let "a" be the acceleration, v_i = 30m/s (initial speed), v_f = 0 -final speed, F -force of friction,  "m" - mass. If the distnace traveled is "d", then we have

 

                                  2ad = v_f² - v_i² = -900 m²/s²

The force of friction is acting in opposite direction. Thus,

 

                       a =  F/m = - 6000 N/1200 kg = - 5m/s²

 

We obtain for d (after canceletaions)

 

                             d = 900m/2x5 = 90 m

      

Answer 3

Numerical answer only please... :)

90 m

 

(see your previous problem)