I know the answers to these questions, but why didn\'t we take gravity as a vert

Question

I know the answers to these questions, but why didn't we take gravity as a vertical force in these questions and subtract them? All we needed to do in these questions is find Fx and Fy and find the net force. But why wasn't gravity/normal for accounted for in the Fy? 1) A boat has a mass of 6800 kg. Its engines generate a drive force of 4940 N due west, while the wind exerts a force of 840 N due east and the water exerts a resistive force of 1900 N due east. Take west to be the positive direction. What is the boat's acceleration, with correct sign? 2) Two horizontal forces, and , are acting on a box, but only is shown in the drawing. can point either to the right or to the left. The box moves only along the x axis. There is no friction between the box and the surface. Suppose that = +3.1 N and the mass of the box is 3.3 kg. Find the magnitude and direction of when the acceleration of the box is (a) +7.1 m/s2, (b) -7.1 m/s2, and (c) 0 m /s2. GRAVITY WAS ACCOUNTED FOR IN THIS PROBLEM: 3) A rocket of mass 3.72

Explanation / Answer

A)

4940 - 840 - 1900 =

2200 N

Use: F = m x a <---->

a = F/m ----->

a = 2200/6800

= 0.3235294117647059 ms^(-2)

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---