An advertisement shows a 1239 kg car slowly pulling at constant speed a large pa

Question

An advertisement shows a 1239 kg car slowly pulling at constant speed a large passenger airplane to demonstrate the power of its newly-designed 78.7-hp (horsepower) engine. During the pull, the car passed two landmarks spaced 26.0 meters apart in 13.3 seconds. The passenger plane being towed is a Boeing 707, with a total weight of 62.5 tons. Calculate the force that opposes the motion. Assume that the efficiency of the car is such that 22.0% of the engine power is available to propel the car forward. Number How much work is performed by the car on the airplane during this time? Number How much work is performed by the airplane on the car during this time? Number

Explanation / Answer

Mass of the car m = 1239 kg

Power of the engine P = 78.7 hp = 78.7 x745.7 = 58686.58 Watt ( as 1 hp = 745.7 W)

Distance traveled by plane (d)= 26 m

Time taken (t) = 13.3 s

speed of the car v = d/t = 26 / 13.3

                        = 1.95 m/s

as only 22% of power is used for moving car forward

P'' = 0.22x (58686.58) W

                    = 12911.05 W

1)

Now this power is used to pull the plane

P'' = Fv ( where v = speed of plane)

12911.05 = F x 1.95

F = 6621.05 N

2)

work done by car = Wc = F x d

= 6621.05 x 26

= 172147.3 J

or = 1.72 x105 j

3) work done by plane on car = - ( work done by car on plane)

= - 172147.3 J

answer

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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