physics questionphy

Question

An airplane has a mass of 3.1 ! 104 kg and takes off under the influ-

ence of a constant net force of 3.7 ! 104 N. What is the net force that

acts on the plane’s 78-kg pilot?

Answer 1

Use F_plane=m_planea to find the acceleration of the plane.

Then, since the pilot experiences the same acceleration, use F_pilot=m_pilota to find the force the pilot experiences. If you want to think like a physicist, use algebra to get an expression for F_pilot as a function of the values you're given.

You should draw a freebody diagram for the pilot and the plane as an aid to doing this problem. If you're not sure how to do that, look up "Freebody Diagram" on the internet and refer to things like the Khan academy treatments.

Answer 2

Our guiding equation here will be F_net = ma. Here, F_net is the net force that an object experiences, m is the mass of that object, and a is the acceleration of that object. We apply this equation first to the airplane, to figure out its acceleration. Then we apply the same equation to the pilot to figure out the force on that pilot.

Here we go:

1) Airplane --

Variables: m = 3.1x10⁴ kg, F_net = 3.7x10⁴ N, a = ?

Equation: 3.7x10⁴ = (3.1x10⁴)a --> a = 1.19 m/s²

2) Pilot --

Variables, m = 78 kg, a = 1.19 m/s², F_net = ?

Equation: F_net = 78 x 1.19 = 93 N