speed of 10mi/hr to2.5 mi/hr in one minute. Calculates the constant rate of accelaration and determine how long the cyclist will take to come to rest.

Question

qwertyuiop

Answer 1

Let v=v₀+at where v₀=10mph, a is the acceleration, t=1 minute=1/60 of an hour, and v=2.5mph.

2.5=10+a/60, a/60=-7.5, a=-450 mph/h or -7.5mph/min.

In other words, it’s the change of speed divided by the time. In this case the change is negative so the acceleration is a deceleration of 7.5mph/min.

So now we have v=v₀-7.5t where t is now in minutes. When v=0 (at rest), 7.5t=v₀, t=10/7.5=4/3=1min 20sec.