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

A motorized winch is pulling a supply pallet across a rough concrete loading dock. The winch applies a constant horizontal pulling force of 1,500 N1,500 \text{ N}. The kinetic friction between the pallet and the dock is 300 N300 \text{ N}. If the pallet accelerates at 1.5 m/s21.5 \text{ m/s}^2, what is the mass of the pallet?

  1. A
    80 kg80 \text{ kg}
  2. 800 kg800 \text{ kg}Cevap
  3. C
    1,000 kg1,000 \text{ kg}
  4. D
    1,800 kg1,800 \text{ kg}

Cevap

The correct mass of the pallet is 800 kg800 \text{ kg}.
The correct answer is found by first determining the net force acting on the pallet. Subtracting the 300 N300 \text{ N} friction from the 1,500 N1,500 \text{ N} applied pulling force yields a net force of 1,200 N1,200 \text{ N}. Using Newton's Second Law (F=maF = ma), dividing the net force by the acceleration (1.5 m/s21.5 \text{ m/s}^2) gives a mass of 800 kg800 \text{ kg}.

Adım Adım Çözüm

1
Calculate the net force acting on the pallet by subtracting the friction force from the applied pulling force.
Fnet=1,500 N−300 N=1,200 NF_{net} = 1,500 \text{ N} - 300 \text{ N} = 1,200 \text{ N}
Newton's Second Law requires the total net force acting on the object, so all opposing forces must be accounted for.
2
Use Newton's Second Law (F=maF = ma) to solve for the mass.
m=Fneta=1,200 N1.5 m/s2=800 kgm = \frac{F_{net}}{a} = \frac{1,200 \text{ N}}{1.5 \text{ m/s}^2} = 800 \text{ kg}
Mass is equal to the net force divided by the resulting acceleration.

Anahtar Kavram

Newton's Second Law (F=ma) and Net Force
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Newton's Second Law (F=ma)

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