A car that weighs 1.5×104 N is initially moving at a speed of 45 km/h when the brakes are applied and the car is brought to a stop in 12 m. Assuming that the force that stops the car is constant, find the magnitude of that force.(adsbygoogle = window.adsbygoogle || []).push({});

I found the mass to be 1.53e3 kg then I figured now I need to find the acceleration using the information that I have so I used the equation

Vf^2 = Vi^2 + 2a(Xf-Xi)

Vi = 12.5 m/s

Vf = 0 m/s

Xf = 12m

Xi= 0 m

Then plug the acceleration value into the equation F= ma but apparently that's wrong. Is this the correct method?

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# Homework Help: Magnitude of the force

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