Question

A 9900 N small car is moved by a 650N force. If the car starts from rest, then how fast is it traveling after 111 m? 

Answer 1

a) Let's first find the mass of the car:

$$m=\dfrac{W}{g}=\dfrac{9900\ N}{9.8\ \dfrac{m}{s^2}}=1010\ kg.$$

Then, we can find the acceleration of the car:

$$a=\dfrac{F}{m}=\dfrac{650\ N}{1010\ kg}=0.64\ \dfrac{m}{s^2}.$$

Finally, we can find the velocity of the car after it traveled 111 meters:

$$v_f^2=v_i^2+2ad,$$ $$v_f=\sqrt{v_i^2+2ad},$$ $$v_f=\sqrt{0+2\cdot0.64\ \dfrac{m}{s^2}\cdot111\ m}=12\ \dfrac{m}{s}.$$