(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A 5400 kg helicopter accelerates upward at 2.17 m/s2. The acceleration due to gravity is 9.8 m/s2. What life force is exerted by the air on the propellers? Answer in N.

2. Relevant equations

Fnet=ma

3. The attempt at a solution

I am making the acceleration positive (2.17m/s2) and the gravitational acceleration negative (-9.8 m/s2) since the helicopter is travelling upwards.

F(lift) - F(gravity) = ma

F(lift) - (5400kgx(-9.8m/s2)) = (5400kg)(2.17 m/s2)

F(lift) = 11718-52920 N

F(lift) = -41202 N

Shouldnt the lift force acting upon the propellers by positive?

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# Homework Help: Net Force

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