Question

In an extreme test of its braking system under ideal road conditions, a Toyota Celica, travelling initially at 26.9 m/s [S], comes to a stop in 2.61 s. The mass of the car with the driver is 1.18 × 103 kg. Calculate :

(a) the car’s acceleration 

(b) the net force required to cause that acceleration

Answer 1

a)

$$a=\dfrac{v-v_0}{t}=\dfrac{0-26.9\ \dfrac{m}{s}}{2.61\ s}=-10.3\ \dfrac{m}{s^2}.$$

b)

$$F_{net}=ma=1.18\times10^3\ kg\times(-10.3\ \dfrac{m}{s^2})=-12154\ N.$$