Recent content by BetoG93

1. Fluid Mechanics of a metal cube

What is the title of the book?
2. Fluid Mechanics of a metal cube

I think the same. Are you sure this is the correct answer?
3. Relativistic Velocity Transformations

No, you can't have a speed greater than c. In relativity, you must use Lorentz's velocity transformation equations.
4. Fluid Mechanics of a metal cube

That extra force you mention is in fact the weight of the cube.
5. Inclined plane with spring underneath.

To find the difference in height, try 1.6 m - (0.18 m) sen 40°. Calculate gravitational energy and equate it to elastic potential energy.
6. Inclined plane with spring underneath.

The height h doesn't depends of inclination; it is measured from the ground. From the drawing you made, it is clear that not all gravitational potential energy goes into compressing the spring, if you take ground as a point of 0 gravitational potential energy. Try to find the difference in...
7. Inclined plane with spring underneath.

A spring is comprensed or stretched along only one axis. That said, it seems that the confusion here is what must we use as x. If 12 cm (0.12 m) is the compressed lenght, then x = 0.12 m. But if 0.12 m is the final lenght of the spring, x would be instead 18 cm. One question: is the spring...
8. Kinetic and Potential Energy on Ramps

Part of the kinetic energy is lost due to friction, and part is converted to gravitational potential energy. Ef - Ei = -Fd = mgh - (1/2)mv^2
9. Rotational equilibrium question

Right, the rope makes an angle of 100° with the body. With this in mind, you can draw a component vector that begins from the body and goes up to the tip of the tension vector, in such way that the component is perpendicular to the body. You have then a 90°-80°-10° triangle, from which you can...
10. Using hookes law to find impulse

Find the function F that defines force (it is a sine or cosine, from what you told). Integrate it over the time interval from 0 to 2 seconds.
11. Two cylinders rolling without slipping

Yes, friction forces are applied at different distances from the axis. That said, the torque is greater for cilinder A, and it comes first. One question: is the lower part of cilinder B contributing to normal force? If it isn't, the problem is now solved.
12. Two cylinders rolling without slipping

I got it. The difference in the radius of cilinder A and the radius of the bits of cilinder B should account for the difference in angular speed...
13. Two cylinders rolling without slipping

But, if the inner surfaces that are in contact to the two sides (bases) of the cilinder are not frictionless, there would be a reduction of the torque... And it would also reduce kinetic energy... Anyway, ignoring that, all seems to indicate that they come at the same time.
14. Two cylinders rolling without slipping

But, if the inner surfaces that are in contact to the two sides (bases) of the cilinder are not frictionless, there would be a reduction of the torque... And they would also reduce kinetic energy... Anyway, all seems to indicate that they come at the same time.
15. Two cylinders rolling without slipping

If both cilinders have the same normal force (which is evenly distributed in the bits), then the friction force is the same, and they come to the floor at the same time. Cilinder B could be lower than A, but I think we can ignore this.