Un cuerpo se mueve en línea recta segun la ecuación x=10+20t-4.9t2 (x está expresado en metros y t en segundos). ¿Cuál es la lon

Objects in vertical motion are an illustration of non-uniform motion. At the peak of the circle, centripetal force is balanced by the object's weight. Therefore, the minimum speed required at this top point is given by v = = = 5.23 m/s. As the sphere descends from the top to the bottom of the circle, according to the law of conservation of energy, potential energy can be expressed as

, where h signifies the diameter of the circle (2r). Hence, the expression will be written as

where u is the velocity at the lowest point. Consequently, the modified equation is

=

=

= 11.71 m/s. The collision of the dart with the bullet is an inelastic one. According to the conservation of momentum: v =

=

=

= 58.55 m/s. Thus, the dart's minimum initial speed for the combined system to complete a circular loop post-collision is 58.55 m/s.

Displacement stabilizes over time. It is known that exponentials raised to infinity approach zero, hence the system model will yield as time approaches infinity, resulting in 4x'' + e−0.1tx = 0. As time approaches infinity, we deduce that 4x'' equals zero. Consequently, upon integrating, we derive 4x' = c, and further integration leads to the conclusion 4x = cx + d.

Answer: damping coefficient = 1.5×10^5Ns/m

Explanation:

Refer to the attached file for the solution

Part 1) Which metal will cool the fastest?
To determine this, we need to consider the heat flow rate formula, which indicates the speed at which a substance can gain or lose heat:

where:
denotes the heat exchanged
indicates the duration
k represents the thermal conductivity of the material
A is the area over which heat transfer takes place
shows the change in temperature
x is the thickness of the substance
It is evident that the heat flow rate is directly related to k, the thermal conductivity. Thus, a higher value of k means that the metal will cool more quickly.
Upon examining the thermal conductivity values for each metal, we observe:
- Aluminium: 237 W/(mK)
- Copper: 401 W/(mK)
- Gold: 314 W/(mK)
- Platinum: 69 W/(mK)
Consequently, copper has the highest heat flow rate, making it the metal that cools the fastest.

Part 2) Which sample of copper demonstrates the greatest increase in temperature
To address this part, we can examine how the heat exchanged Q correlates with temperature increase :

where m indicates the mass and Cs represents the specific heat capacity of the material. By rearranging the equation, we derive

As a result, it becomes clear that the temperature increase is inversely related to the mass m. Thus, the block exhibiting the highest temperature rise will be the one with the least mass, hence the right choice is A) 0.5 kg.

Answer:

Explanation:

The wavelength of sound can be calculated using the formula: wavelength = velocity / frequency.

Thus, it becomes:

λ = 340 / 170

λ = 2 m.

When the person stands ideally in the center between the speakers, the sound waves reaching him are perfectly aligned (no path difference), resulting in maximum sound intensity.

As he moves closer to one of the speakers, his proximity to that speaker increases while the distance to the other speaker decreases, creating a path difference in the sound waves reaching his ears.

If he walks 0.5 m toward one speaker, the created path difference becomes:

0.5 x 2 = 1 m.

This path difference equals λ / 2, leading to destructive interference, resulting in minimal sound being audible.

As he continues walking a full 1 m, the created path difference totals 2 m.

This corresponds to a path difference of λ, causing constructive interference and maximum sound perception.

Finally, if he moves an additional 1.5 m, the resulting path difference increases to 3 m.

Thus, we arrive at a path difference of 3 λ / 2, producing destructive interference once more, leading to minimum sound being perceived again.

In summary, the man begins at a maximum intensity point, moves to minimum intensity, then back to a maximum, and ultimately ends at another minimum sound intensity position.