Kinematics Question. Incline, Spring, Friction

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SUMMARY

The discussion focuses on solving a kinematics problem involving an incline, spring, and friction for a midterm practice question. Key equations include the conservation of energy equation T_1 + U_1 = T_2 + U_2 and the spring potential energy formula U_spring = 1/2 kx^2. The participant struggles with incorporating the friction constant into the calculations, specifically distinguishing between static and kinetic friction forces. The correct approach requires comparing the spring force with the static friction force to determine the conditions for the block to move from rest.

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  • Understanding of kinematics and dynamics principles
  • Familiarity with spring mechanics and Hooke's Law
  • Knowledge of friction types: static and kinetic
  • Ability to apply conservation of energy in mechanical systems
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  • Study the relationship between spring force and static friction force in detail
  • Learn how to calculate static and kinetic friction coefficients
  • Explore energy loss due to friction in mechanical systems
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Students preparing for physics exams, particularly those focusing on mechanics, as well as educators seeking to enhance their teaching methods in kinematics and dynamics.

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Homework Statement


Practice problem for midterm.
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Homework Equations


[/B]
T_1+U_1=T_2+U_2
U_spring=1/2kx^2

The Attempt at a Solution


[/B]
Set X-axis along the 30 degree line and the Y-axis perpendicular.

I'm not sure how to consider the friction constant into the formula.

Any help is very much appreciated.
 
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hint: work against friction.
 
Calculate the friction forces (static and kinetic). Make sure the block can move when released (static friction). If the block moves against friction (kinetic friction), what work is done? What happens to the energy involved in friction?
 
sumF_y=0
N-mgcos30=0
N=17 N

sumF_x=0
F_spring-F_friction=m_block*accel_block
kx-uN=ma

if static, accel=0

410(0.5)-u(17)=0
u=12.06

doesnt seem right... i think the x is wrong for the spring but i can't visualize it.
 
You want to compare the spring force with the static friction force. What must the relationship be if the block is to be able to move from rest?
 

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