Homework Help: physics

Posted by Mary on Saturday, March 10, 2012 at 8:35pm.

A small plane mass 600 kg lifts off from the runway at a speed of 145 Km/Kr. 2 Minutes later, the plane has reached an altitude of 300 meters and its airspeed has dropped to 90 Km/Hr. Assume the power output of the engine was constant during this time. Ignore air resistance and compute the HP (horsepower) produced by the engine.

physics - drwls, Sunday, March 11, 2012 at 7:38am
Divide total energy gain by 120 seconds for the energy of power delivered by the engine.

P.E. gain = M g H = 1.746*10^6 J
K.E. loss = (M/2)(V1^2 - V2^2)
V1 = 40.28 m/s
V2 = 25.00 m/s
K.E. loss = 2.992*10^5 J
Net energy gain = 1.465*10^6 J
Power during interval = 1.465*10^6/120 = 12210 W = 164 horsepower

This is an underestimate because there is also air friction drag that the engine must overcome, and because the propellers are not 100% efficient

Answer this Question

Related Questions

physics - An airplane needs at least 145 meters of runway to take off. If the ...
Physics - A jet plane lands with a speed of 110 m/s and can accelerate with a ...
physics- pls help me - 1. The driver of a car slams on the brakes when he sees a...
physics - A jet plane lands with a speed of 110 m/s and can decelerate uniformly...
Physics - A jet plane lands with a speed of 120 m/s and can decelerate uniformly...
Physics - A small plane takes off with a constant speed of 130 km/h at an angle ...
physics - A small plane starts down the runway with acceleration 7.4 .if the ...
help - A. A light plain is coming in for a landing at a speed of 100 km/hr. The ...
physics - The airplane can take off when its airspeed (speed of the air flowing ...
physics - The airplane can take off when its airspeed (speed of the air flowing ...

For Further Reading

First Name:
School Subject:
Answer: