Question

An aeroplane of mass 17000kg lands with a velocity of 75m/s reverse thrust from the engines slows it to a speed of 25m/s in a distance of 230m. What is the size of the reverse thrust supplied by the engines

Answer 1

$$V^2-v^2=2as$$

$$\left(\frac{75}{3.6}\right)^2-\left(\frac{25}{3.6}\right)^2=2(230)a$$

$$a=0.8387\frac{m}{s^2}$$

$$F=ma=(17000)(0.8387)=14258\ N$$