# Tag Info

Accepted

This is an interesting problem, and it turns out that you can solve for it exactly using the technique of normal coordinates. I'll try to give you the general outline of how it works in this case ...
• 42.2k
Accepted

### Critical force for a system comprised of a compressible and incompressible parts

We assume two general bars/rods/beams in parallel with Young's elastic modulus, cross-sectional area, and area moment of inertia $E_1$, $A_1$, $I_1$ and $E_2$, $A_2$, $I_2$, respectively. Beam 1 is ...
• 18.2k
Accepted

### "Spherical wave" in a 2D square lattice of masses and springs

To see how the square lattice determines how a wave looks at large distance, let me copy from my notes how response of the slightly simpler problem of how the solution of a massive scalar wave ...
• 45.7k
1 vote
Accepted

### Why do cars move slightly backwards just before coming to rest?

A car's suspension is not designed to allow the wheels to shift fore and aft relative to the chassis. This would cause the steering geometry to vary under acceleration and deceleration and make the ...
• 80.8k
1 vote

### Why do cars move slightly backwards just before coming to rest?

The reason here might be because of the elastic nature of tire and chassis, as they might store some potential energy if you suddenly stop the wheel, because the whole body will still be in motion as ...
• 830
1 vote

### If a plank is moving horizontally on a solid cylinder with a spring attached to it on a wall, why is its velocity twice the velocity of the cylinder?

I assume the speed of the cylinder (v) is defined as the speed of its centre of mass, which should be at the axle. At any point in time while the cylinder is rolling, the current speed of its top ...
• 11
1 vote

### Convention when considering a mathematical pendulum attached to an object with a spring

The value of the potential energy is not important. It may be positive or negative. All that matters is that the gravitational potential energy should be greater at the top and lower at the bottom. ...
• 78k
1 vote

### How to find velocity at natural length when total mechanical energy is negative?

Your arithmetic is correct. As you say, a solution of $v=\sqrt{-8}$ when $x=1$ is unrealistic. This tells you that the particle never reaches $x=1$, so the spring is always longer than its natural ...
• 39.6k

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