Q4-32DQ A manual for student pilots cont... [FREE SOLUTION]

91影视

University Physics with Modern Physics

Hugh D. Young, Roger A. Freedman

Physics

14th edition Edition 路 1596 pages

ISBN: 9780321973610

Chapter 1: Q4-32DQ (page 123)

A manual for student pilots contains this passage: 鈥淲hen an airplane flies at a steady altitude, neither climbing nor descending, the upward lift force from the wings equals the plane鈥檚 weight. When the plane is climbing at a steady rate, the upward lift is greater than the weight; when the plane is descending at a steady rate, the upward lift is less than the weight.鈥� Are these statements correct? Explain.

Short Answer

Expert verified

The statements are correct following Newton's second law of motion.

Step by step solution

Definition of Newton’s second law of motion

According to Newton's second law of motion the net force acting on a body is equal to its mass times its acceleration.

Determining the net force on an airplane

The net vertical force acting on an airplane is the difference of the upward lift and its weight. When the plane is neither climbing nor descending its vertical acceleration is zero. From the second law the net vertical force is also zero. Thus the upward lift cancels the weight and is equal to it.

Similarly, when the plane is climbing there is an upward acceleration and thus a net upward force. Hence the upward lift is greater than the weight. When the plane is descending there is a downward acceleration and thus a net downward force. Hence the upward lift is smaller than the weight.