Originally Posted by

**bradycat** Need help on this.

A car whose mass is 2600 kg can produce an unbalanced braking force of 2765N.

Calculate the car's initial speed in order to have a stopping distance of 3036.3m.

Vi=?

So...

m=2600kg

F=2765N

s=3036.3m

Vf=0

So I found acceleration of a=F/m = 2765/2600 = 1.06346m/s^2

So I have to find time=Square root of 2(3036.33)/1.06346 = 75.56605s

So I would use this formula to solve for Vi? right

Vi=Vf -at

Vi = 0 - (1.06346)(75.56605) = -80.3614 m/s

Is the negative right?

IS THIS CORRECT if not please show me where I went wrong

Thanks

Jo

Code:

So I found acceleration of a=F/m = 2765/2600 = 1.06346m/s^2

that should be minus. -2765 and -1.06346m/s^2

s=vt-0.5*a*t^2

3036.3=0-0.5*-1.06346*t^2

3036.5/(0.5*1.06346)=t^2

t=75.56605s

Vi = 0 - (-1.06346)(75.56605) = 80.3614 m/s