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As shown in the figure, the mass of an object m = 2kg is at point a on the inclined plane with an inclination angle of θ = 37 ° When the object reaches B, the spring will be compressed to point C with the maximum compression BC = 0.2m, and then the object will be bounced up again by the spring. The highest position of bounce is point D, and the distance between point D and point a is ad = 3M. The mass of baffle and spring is not included, and g = 10m / S ^ 2, sin37 ° = 0.6, Find: (1) the dynamic friction coefficient μ between the object and the inclined plane. (2) the maximum elastic potential energy E of the spring
(1) For the object m, from the beginning of motion to its reaching D, the reduced mechanical energy is mg * (ad * sin θ) + 0.5m * V0 ^ 2. The work done to overcome the friction is equal to the product of the friction and the distance: μ mg * (AC + CD) cos θ
Mg * (ad * sin θ) + 0.5m * V0 ^ 2 = μ mg * (AC + CD) cos θ is substituted to calculate μ =
(2) When the compression of the spring is the maximum, that is, when the object reaches the lowest point C, the spring has the maximum elastic potential energy. From a to C, the mechanical energy of the object decreases=
Mg * (AC) sin θ + 0.5m * V0 ^ 2 = μ mg * (AC) * cos θ + e is calculated
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