physics help please ?

air exerts a forward force of 8 N on the propeller of a 0.15 kg model airplane. If the plane accelerates forward at 1.6 m/s^2 , what is the magnitude of the resistive force exerted by the air on the airplane? Answer in units of N 

An elevator starts from rest with a constant
upward acceleration and moves 1 m in the first
1.9 s. A passenger in the elevator is holding a
5 kg bundle at the end of a vertical cord.
What is the tension in the cord as the elevator accelerates? The acceleration of gravity
is 9.8 m/s^2


Answer in units of N

billrussell422020-11-06T17:48:49Z

net force F = ma = 0.15•1.6 = 0.24 N
Fr = 8 – 0.24 = 7.76 N

moves 1 m in the first 1.9 s.
d = ½at²
1 = ½a(1.9)²
a = 2/(1.9)² = 0.554 m/s²

on the bundle, F = ma = 5•0.554 = 2.77 N due to elevator
force due to weight = mg = 5•9.8 = 49 N
total is tension of 51.77 N, rounded to 52 N

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