- #31
Tanya Sharma
- 1,541
- 135
Satvik Pandey said:
I am glad you were able to solve the problem
Mechanics problem -- 2 masses & spring on a surface
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Homework Help Overview
The discussion revolves around a mechanics problem involving two masses (M1 and M2) and a spring on a surface. The goal is to determine the minimum force required to move the second mass (M2) while considering the effects of friction and the spring's force.
Discussion Character
- Mixed
Approaches and Questions Raised
- Participants explore the relationship between the forces acting on the blocks, including friction and the spring force. There are attempts to derive equations based on free body diagrams and to clarify the role of the spring constant (k). Questions arise about the nature of the forces involved and whether the work-energy theorem is applicable.
Discussion Status
Several participants express differing views on the approach to solving the problem, with some suggesting that the initial analysis may not yield the minimum force required. There is ongoing exploration of the conditions under which M1 must move before M2, and discussions about the implications of using static versus kinetic friction. The conversation reflects a productive exchange of ideas without reaching a consensus.
Contextual Notes
Participants note that the value of the spring constant (k) is not provided, and there are questions about the initial conditions of the system, such as whether the motion starts from rest. The discussion also highlights the importance of understanding the distinction between equilibrium conditions and the minimum force required for motion.
I am glad you were able to solve the problem
- #32
ehild
Science Advisor
Homework Helper
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Satvik Pandey said:
Your approach assumed that both masses are moving. Only in that case are the forces of friction μmg. If one of the mass is in rest, friction is static. Can be less than μmg.
The masses in the problem can move in a peculiar way. Initially both are in rest, so the force F has to overcome μ1m1g and the elastic force of the spring. But the other mass is in rest, till the elastic force overcomes the frictional force acting to it. At the same time, the first mass can get into rest, and the elastic force alone drives the second mass forward. So the average applied force can be less than μ1m1g+μ2m2g.
ehild