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:
[tex]F_{g} = m*g = 2.8 kg*(-9.8m/s2) = -27.4 N (1)[/tex]
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:
[tex]F_{net} = T -F_{g} = 32.6 N - 27.4 N = 5.2 N (2)[/tex]
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:
[tex]a = \frac{F_{net} }{m} = \frac{5.2N}{2.8kg} = 1.9 m/s2 (3)[/tex]
