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Zorluk: ZorNewton's Second Law (F=ma)

A twin-engine military cargo aircraft with a total mass of 80,000 kg80,000 \text{ kg} is accelerating down a runway for takeoff. Each of the two engines generates 140,000 N140,000 \text{ N} of forward thrust. If the combined forces of rolling friction and aerodynamic drag opposing the aircraft's motion amount to 80,000 N80,000 \text{ N}, what is the forward acceleration of the aircraft in m/s2\text{m/s}^2?

Cevap: 2.5 m/s^2

Cevap

The forward acceleration of the aircraft is 2.5 m/s².
To accurately determine the acceleration, one must first find the net force acting on the aircraft. The total forward thrust is the sum of both engines (140,000 N×2=280,000 N140,000 \text{ N} \times 2 = 280,000 \text{ N}). Subtracting the opposing forces of friction and drag (80,000 N80,000 \text{ N}) yields a net forward force of 200,000 N200,000 \text{ N}. Dividing this net force by the aircraft's mass of 80,000 kg80,000 \text{ kg} gives a forward acceleration of 2.5 m/s22.5 \text{ m/s}^2.

Adım Adım Çözüm

1
Calculate the total forward thrust applied to the aircraft.
2×140,000 N=280,000 N2 \times 140,000 \text{ N} = 280,000 \text{ N}
The aircraft has two engines, and the problem provides the thrust generated by each individual engine.
2
Calculate the net force (FnetF_{net}) acting on the aircraft.
Fnet=280,000 N−80,000 N=200,000 NF_{net} = 280,000 \text{ N} - 80,000 \text{ N} = 200,000 \text{ N}
Net force is the vector sum of all forces. The opposing forces (drag and friction) must be subtracted from the forward thrust.
3
Apply Newton's Second Law to calculate the acceleration.
a=200,000 N80,000 kg=2.5 m/s2a = \frac{200,000 \text{ N}}{80,000 \text{ kg}} = 2.5 \text{ m/s}^2
According to Newton's Second Law, acceleration equals the net force divided by the mass (a=Fnetma = \frac{F_{net}}{m}).

Anahtar Kavram

Newton's Second Law of Motion (Fnet=maF_{net} = ma)
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