Question

A jet plane lands with a speed of 109 m/s and can accelerate at a maximum rate of −5.80 m/s2 as it comes to rest.(a) From the instant the plane touches the runway, what is the minimum time needed before it can come to rest?_____ s

Answer 1

The time it takes for a particle with an acceleration a to change its velocity from v_0 to v_f is given by:

$t=\frac{v_f-v_0}{a}$

Replace v_f=0, v_0=109m/s and a=-5.80m/s^2:

$t=\frac{(0)-(109\frac{m}{s})}{-5.80\frac{m}{s^2}}=18.793...s\approx18.8s$

Therefore, the answer is: 18.8s.