Two boats are racing across a lake, which is 60.0 km across. To win, a boat must

Question

Two boats are racing across a lake, which is 60.0 km across. To win, a boat must traverse the lake and return to its original point. Boat A crosses the lake at 60.0 km/h and returns at the same speed, and boat B crosses the lake at 30.0 km/h and returns at 90.0 km/h. a) Which boat wins? Give the total time for each boat. b) How far behind, in km, is the losing boat from the winning boat when it wins? c) What are the average velocities of boats A and B? What are their average speeds? In class we discussed how to obtain a v - t plot from an a-i plot. Specifically, we took the example of an object that accelerates at 2.0 m/s^2 during 0.0

Explanation / Answer

From the given question,

1. total distance = 120 km

whichever boat takes less time will win.

time taken by boat A= (60/60) + (60/60)= 2 hr

time taken by boat B= (60/30) + (60/90)= 2 hr 40 min

So, boat A will win.

b) distance travelled by losing boat after 2 hr= 2*30=60 km

Tle losing boat is 60 km behind, when the other boat wins.

c) average velocity= (total displacement)/(total time)

average speed= (total distance)/(total time)

since both the boats return to starting point, their displacement is zero.

hence, average velocity of both the boat is zero.

average speed of boat A = (120)/2= 60 km/hr

average speed of boat B= (120)/(2.67)= 45 km/hr

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.