Question

A novice captain is pointing his ferryboat directly across the river at a speed of 15.7 mi/h. If he does not pay attention to the current that is headed downriver at 5.35 mi/h, what will be his resultant speed and direction? (Consider that the current and the boat’s initial heading are perpendicular to each other.)

Answer 1

Anette is a civil engineer and needs to determine the length of a highway on-ramp before construc- tion begins. If the average vehicle takes 10.8 s to go from 20.0 mi/h to 60.0 mi/h, how long should she design the separate merge lane to be so a car can reach a speed of 60.0 mi/h before merging?

Answer 2

Vr = 5.35 + 15.7i = 16.7 mi/h[71.2o] = Resultant velocity.

Answer 3

Vo = 20mi/h * 1600m/mi * 1h/3600s = 8.89s.

V = 60mi/h = 26.7 m/s.

a = (V-Vo)/t = (26.7-8.89)/10.8 = 1.65 m/s^2.

d = Vo*t + 0.5a*t^2