You are an industrial engineer with a shipping company. As part of the package-handling system, a small box with mass 1.60 kg is placed against a light spring that is compressed 0.280 m. The spring, whose other end is attached to a wall, has force constant k = 48.0 N/m. The spring and box are released from rest, and the box travels along a horizontal surface for which the coefficient of kinetic friction with the box is μk = 0.300. When the box has traveled 0.280 m and the spring has reached its equilibrium length, the box loses contact with the spring.

A. What is the speed of the box at the instant when it leaves the spring?
Express your answer with the appropriate units

B.What is the maximum speed of the box during its motion?
Express your answer with the appropriate units.

Respuesta :

Answer:

a) [tex]v \approx 2\,\frac{m}{s}[/tex], b) [tex]v \approx 2\,\frac{m}{s}[/tex]

Explanation:

a) The package handling system is modelled by using the Principle of Energy Conservation and the Work-Energy Theorem:

[tex]U_{k} = K_{t} + W_{loss}[/tex]

The final kinetic energy is:

[tex]K_{t} = U_{k} - W_{loss}[/tex]

[tex]\frac{1}{2}\cdot m \cdot v^{2} = \frac{1}{2}\cdot k \cdot x^{2} + \mu_{k}\cdot m\cdot g\cdot x[/tex]

[tex]v^{2} = \frac{k}{m} \cdot x^{2} + 2\cdot \mu_{k}\cdot g\cdot x[/tex]

The final speed is:

[tex]v = \sqrt{\frac{k}{m}\cdot x^{2}+2\cdot \mu_{k}\cdot g \cdot x }[/tex]

[tex]v = \sqrt{\frac{48\,\frac{N}{m} }{1.60\,kg}\cdot (0.280\,m)^{2}+2\cdot (0.3)\cdot (9.807\,\frac{m}{s^{2}} )\cdot (0.280\,m) }[/tex]

[tex]v \approx 2\,\frac{m}{s}[/tex]

b) The maximum speed of the box during its motion occurs at the beginning of the movement, since the work done by friction is non-conservative and reduces speed as box travels on the horizontal surface. Hence, the maximum velocity is:

[tex]v \approx 2\,\frac{m}{s}[/tex]