Читать книгу Flight Theory and Aerodynamics - Joseph R. Badick - Страница 44

Note: Answers to problems are given at the end of the book.

1 Convert 65 kts. to fps.

2 Convert 200 fps to kts.

3 Convert 35 kts. to fpm.

4 Convert 52 nm to sm.

5 An airplane weighs 16 000 lb. The local gravitational acceleration g is 32.2 fps2. What is the mass of the airplane?

6 The airplane in Problem 5 accelerates down the runway with a net forward force (thrust less drag) of 6000 lb. Find the acceleration of the airplane.

7 The airplane in Problem 6 starts from a brakes‐locked position on the runway. The airplane takes off at an airspeed of 200 fps. Find the time for the aircraft to reach takeoff speed.

8 Under no‐wind conditions, what takeoff roll is required for the aircraft in Problem 7?

9 Upon reaching a velocity of 100 fps, the pilot of the airplane in Problem 7 decides to abort the takeoff and applies brakes and stops the airplane in 1000 ft. Find the airplane’s deceleration.

10 An airplane is towing a glider to altitude. The tow rope is 20° below the horizontal and has a tension force of 300 lb exerted on it by the airplane. Find the horizontal drag of the glider and the amount of lift that the rope is providing to the glider. Sin 20° = 0.342; cos 20° = 0.940.

11 A jet airplane is climbing at a constant airspeed in no‐wind conditions. The plane is directly over a point on the ground that is 4 statute miles from the takeoff point and the altimeter reads 15 840 ft. Find the plane’s climb angle and the distance that it has flown through the air.

12 Find the distance s and the force F on the seesaw fulcrum shown in the figure. Assume that the system is in equilibrium.

13 A helicopter has a rotor diameter of 30 ft and it is being operated in a hover at 286.5 rpm. Find the tip speed Vt of the rotor.

14 An airplane weighs 16 000 lb and is flying at 5 000 ft altitude and at an airspeed of 200 fps. Find (a) the potential energy, (b) the kinetic energy, and (c) the total energy. Assuming no extra drag on the airplane, if the pilot drove until the airspeed was 400 fps, what would the altitude be?

15 An aircraft’s turbojet engine produces 10 000 lb of thrust at 162.5 kts. true airspeed. What is the equivalent power that it is producing?

16 An aircraft weighs 24 000 lb and has 75% of its weight on the main (braking) wheels. If the coefficient of friction is 0.7, find the braking force Fb on the airplane.

17 Newton’s third law of motion states:A body at rest will remain at rest and a body in motion will remain in motion, in a straight line, unless acted upon by an unbalanced force.For every action force there is an equal and opposite reaction force.If a body is acted on by an unbalanced force, the body will accelerate in the direction of the force, and the acceleration will be directly proportional to the force and inversely proportional to the mass of the body.

18 An aircraft parked on an airport ramp would be an example of Newton’s _______ law of motion.first.second.fourth.third.

19 An airplane in level flight increases thrust, resulting in an acceleration until once again thrust equals:aerodynamic force.lift.weight.drag.

20 An airplane in straight‐and‐level, unaccelerated flight weighs 2300 lb, what total lift must the aircraft produce to maintain a constant altitude assuming no additional forces are involved:2000 lb2300 lb1150 lb>2300 lb