A ball of unknown mass m is tossed straight up with initial speed v. At the moment it is released, the ball is a height h above a spring-mounted platform, as shown in the figure below. The ball rises, peaks, and falls back toward the platform, ultimately compressing the spring a maximum distance d from its relaxed position. Assume that the spring is perfectly ideal with spring constant k, and that the mass of the spring and platform is negligible. What is the mass m, assuming that there is no friction or air resistance? Using g to represent the acceleration due to gravity, enter an expression for m in terms of g, h, d, k, and v.

Respuesta :

The sum of the energy in a isolated system is always constant, according to the  Law of Conservation of Energy

[tex]An \ expression \ for \ \mathbf{m} \ is \ m= \mathbf{\dfrac{ k \cdot d^2}{\left(2\cdot g \cdot (h + d) +v^2 \right) }}[/tex]

Reason:

According to the Law of Conservation of Energy, we have;

Mechanical energy of ball = Elastic potential energy gained by spring

M.E. = P.E. + K.E. = [tex]P.E._{spring}[/tex]

The initial potential energy of the ball relative to the compressed spring, P.E. is given as follows;

P.E. = m·g·(h + d)

[tex]The \ kinetic \ energy \ of \ the \ ball\ K.E. = \dfrac{1}{2} \cdot m \cdot v^2[/tex]

[tex]Potential \ energy \ given \ to \ the \ spring \ P.E._{spring} = \dfrac{1}{2} \cdot k \cdot d^2[/tex]

Therefore, we get;

[tex]M.E. = m\cdot g \cdot (h + d) + \dfrac{1}{2} \cdot m \cdot v^2 = \dfrac{1}{2} \cdot k \cdot d^2[/tex]

Which gives;

[tex]m\cdot \left(g \cdot (h + d) + \dfrac{1}{2} \cdot v^2 \right) = \dfrac{1}{2} \cdot k \cdot d^2[/tex]

[tex]m=\dfrac{\dfrac{1}{2} \cdot k \cdot d^2}{\left(g \cdot (h + d) + \dfrac{1}{2} \cdot v^2 \right) } = \dfrac{ k \cdot d^2}{\left(2\cdot g \cdot (h + d) +v^2 \right) }[/tex]

The expression for m in terms of g, h, d, k, and v is therefore;

[tex]m= \dfrac{ k \cdot d^2}{\left(2\cdot g \cdot (h + d) +v^2 \right) }[/tex]

Learn more about the Law of Conservation of Energy here:

https://brainly.com/question/24298627

Ver imagen oeerivona