Question #6e96b

1 Answer

v = 8sqrt(5)"m/s"v=85m/s

Explanation:

Just after bus started
For bus: Displacement, x = (1/2)x=(12) x (0.2)(0.2)t^2t2
For man: Displacement, 80 + x = vt80+x=vt

To get close to the bus:

0.1 * t^2 = vt - 800.1t2=vt80 ; eliminating xx from above two equations

=> t^2 -10vt +800 = 0t210vt+800=0

To get the real solution of the above quadratic equation;

10v^2 - 4 * 1 * 80 >= 010v241800

This means that

v^2 >= 320v2320

so, the minimum speed will be

sqrt(v^2) = sqrt(320) => v = 8sqrt(5)"m/s"v2=320v=85m/s