Question

A cyclist starts from rest and accelerates at 2m/s2, for 2second. Her velocity remains constant for the following 4second. The brakes are then applied and the bicycle decelerates uniformly until it comes to rest after 10 second.
Find(a) the distance moved during each stage of motion.
(b) the average velocity over the whole journey.

Answer 1

V = Vo + a*t = 0 + 2*2 = 4 m/s.

a. d1 = v*t = 4 * 4 = 16 m.

V = Vo + a*t = 0, 4 + a*10 = 0,
a = -0.4 m/s^2.

V^2 = Vo^2 + 2a*d2 = 0, 4^2 - 0.8*d = 0, -0.8d2 = -16, d2 = 20 m.

b. Vavg = (d1+d2)/(t1+t2) = (16+20)/(4+10) = 2.57 m/s.

Answer 2

A cyclist speeds up at a constant acceleration of 2m/s? from rest. Find the velocity of the cyclist after 10 second.

Answer 3

2m