Doppler Effect: A stationary source produces a sound wave at a frequency of 50 Hz. The wave travels at 100 feet per second. A ca
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Answer:
a) Fg = -27.4 N
b) Fnet = 5.2 N
c) a = 1.9 m/s2
Explanation:
a)
- There are two forces acting on the ball, one directed upward (assuming this direction as positive, along the y-axis) which is the tension on the string (lifting force), and another aimed downward, which is the attractive force due to gravity.
- Applying the Newton's Universal Law of Gravitation to a mass close to the surface of the Earth (in this case the ball), we can take the acceleration due to gravity like a constant, that we call by convention g, equal to -9.8 m/s2.
- So, we can write the following expression for Fg:
b)
- The net force on the ball, will be just the difference between the lifting force (32.6 N) and the force due to gravity, Fg:
c)
- According Newton's 2nd Law, the acceleration caused by a net force on a point mass (we can take the ball as one) is given by the following expression:
The gravitational force between <em>m₁</em> and <em>m₂</em> has magnitude
while the gravitational force between <em>m₁</em> and <em>m₃</em> has magnitude
where <em>x</em> is measured in m.
The mass <em>m₁</em> is attracted to <em>m₂</em> in one direction, and attracted to <em>m₃</em> in the opposite direction such that <em>m₁</em> in equilibrium. So by Newton's second law, we have
Solve for <em>x</em> :
The solution with the negative square root is negative, so we throw it out. The other is the one we want,