Answer to Question #79167 in Physics for Sunny

Question

A cyclist starts from rest and accelerates at 2m%2Fs square for 20 seconds. He then travels at a constant speed for 1 minute and then finally decelerates at 3m%2Fs square. Find the maximum speed

Answer 1

Since the speed of the cyclist decreases during the deceleration, the maximum speed he has after the acceleration (after first 20 seconds and during one minute after).
The initial speed v_i, final speed v_f, acceleration a and the time of acceleration t are related by the following expression
v_f-v_i=at
Since v_i=0 m/s, a=2 m/s^2 and t=20 s, we obtain
v_f=v_i+at=0 m/s+2 m/s^2 ∙20 s=40 m/s