A jet plane starts from rest on the runaway and accelerates for takeoff at 2.30 m/s^2 (=7.55 ft/s^2). It has two jet engines, each of which exerts a thrust of 1.40 x 10^5 N (= 15.7 tons). What is the weight of the plane?
If the answer is 1.19 x 10^6 N how would I get there?
~thanks.
If the answer is 1.19 x 10^6 N how would I get there?
~thanks.
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Use Newton's second law, F = m a.
Here F equals twice the thrust of one engine, so 2.80 x 10^5 N in total, and a=2.30 m/s^2 .
From that you find the mass:
m = F / a = 2.80 x 10^5 N / (2.30 m/s^2) = 1.22 x 10^5 kg
With the mass now calculated, the weight follows from
F = m g
= 1.22 x 10^5 kg * 9.81 m/s^2 = 1.19 x 10^6 N
Here F equals twice the thrust of one engine, so 2.80 x 10^5 N in total, and a=2.30 m/s^2 .
From that you find the mass:
m = F / a = 2.80 x 10^5 N / (2.30 m/s^2) = 1.22 x 10^5 kg
With the mass now calculated, the weight follows from
F = m g
= 1.22 x 10^5 kg * 9.81 m/s^2 = 1.19 x 10^6 N