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Three forces acting on a body are given by F1 = (- 2.15i + 2.92j) N, F2 = (4.80i-2.83j) N and F3 = (- 46.6i) N. The object is initially at rest and accelerates by 3.01m / s^2. After 11.4 s, what is your speed along the x axis (the component of the x axis of your speed)?

I did the sum of the forces, I discovered the mass and then I divided the sum by the forces and multiplied by the time, and I found -34.3i.

Jojo
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1 Answers1

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  1. Calculate the net force in vector form
  2. Calculate the magnitude of the net force vector
  3. Use the magnitude of net acceleration (given as 3.01) and the magnitude of net force to calculate the mass
  4. Use the mass and the magnitude of the component of net force on X-axis to calculate the acceleration on X-axis
  5. Use the acceleration on X-axis and the time to calculate the speed

Speed is a magnitude, therefore a positive number. If you need extra help with the calculations please let me know

WindSoul
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  • No finding mass is not necessary. Find the unit vector in the direction of the net force. You can directly multiply by the acceleration magnitude and that gives you acceleration in x and y direction. Multiply acceleration in x-direction by time $t$ and you get velocity at time $t$ in x direction.. – Math Lover May 26 '21 at 14:54
  • I agree that mass calculation could be avoided: $a_x=\frac{F_x}{F}\cdot a\approx 3.01\frac{m}{s^2}$. Then required speed $v_x=\frac{a_x}{t}=\frac{3.01}{11.4}$. – WindSoul May 26 '21 at 15:15