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3 years ago

Some help please physics

Physics

2 answers:

salantis [7]3 years ago

3 0

My best guess is A There is missing a time unit in the question. I know that 4.4 *5 = 21 so that would be my best guess.

REY [17]3 years ago

3 0

The car's AVERAGE speed is (21/2)=10.5 m/s. (Zero at the beginning, 21 at the end.). In order to cover 50m at an average speed of 10.5 m/s, it takes (50/10.5)=4.76 seconds. It took 4.76 seconds to accelerate to 21 m/s^2, so the average acceleration is (21/4.76)=4.2 seconds. You probably had a formula in class that would take you to 4.4, but this is the way I think it through without a lot of formulas.

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A spring is hung from the ceiling. A 0.442-kg block is then attached to the free end of the spring. When released from rest, the

siniylev [52]

Answer:

$K=58.8N/m$

Explanation:

From the question we are told that:

Mass $M=0.442$

Drop distance $d=0.150$

Generally the equation for Spring Constant is mathematically given by

$K=\frac{2mg}{x}$

$K=\frac{2*0.442*9.8}{1.150}$

$K=58.8N/m$

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3 years ago

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3 years ago

What is booklet?<br>how to prepare booklet<br><br>

const2013 [10]

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3 years ago

Three uniform spheres of radius 2R, R, and 3R are placed in a line, in the order given, so their centers are lined up and the sp

kolezko [41]

Answer:

x = 2.33 R from the center of mass of the smallest sphere.

Explanation:

Due to the symmetry of the spheres, the center of mass of any of them, is located just in the center of the sphere.

If we align the centers of the spheres with the x-axis, the center of mass of any of them will have only coordinates on the x-axis, so the center of mass of the system will have coordinates on the x-axis only also.

By definition, the x-coordinate of the center of mass of a set of discrete masses m₁, m₂, m₃, can be calculated as follows:

$Xcm = \frac{m1*x1+m2*x2+m3*x3}{m1+m2+3}$

In this case, we need to get the coordinates of the center of mass of each sphere:

If we place the spheres in such a way that the center of the first sphere has the x-coordinate equal to its radius (so it is just touching the origin), we will have:

x₁ = 2*R

For the second sphere, the center will be located at a distance equal to the diameter of the first sphere plus its own radius, as follows:

x₂ = 4*R + R = 5*R

Finally, for the third sphere, the center will be located at a distance equal to the diameter of the first sphere, plus the diameter of the second sphere, plus its own radius, as follows:

x₃ = 4*R + 2*R + 3*R = 9*R

We can calculate the mass of each sphere (assuming that all are from the same material, with a constant density), as the product of the density and the volume:

m = ρ*V

For a sphere, the volume can be calculated as follows:

$\frac{4}{3} *\pi *(r)^{3}$

So, we can calculate the masses of the spheres, as follows:

m₁ = ρ* $\frac{4}{3} *\pi *(2r)^{3}$

m₂ = ρ* $\frac{4}{3} *\pi *(r)^{3}$

m₃ = ρ* $\frac{4}{3} *\pi *(3r)^{3}$

The total mass can be calculated as follows:

M= ρ* $\frac{4}{3} *\pi$ * (8*r³ + r³ + 27*r³) =ρ* $\frac{4}{3} *\pi$ * 36*r³

Replacing by the values, and simplifying common terms, we can calculate the x-coordinate of the center of mass of the system as follows:

$Xcm = \frac{m1*x1+m2*x2+m3*x3}{m1+m2+3}$

$Xcm = \frac{(8*R^{3} *2*R)+(R^{3}*(5*R))+27*R^{3}*(9*R))}{36*R^{3} }=\frac{264*R^{4} x}{36*R^{3}} = 7.33 R$

As the x-coordinate of the center fof mass of the entire system is located at 7.33*R from the origin, and the center of mass of the smallest sphere is located at 5*R from the origin, the center of mass of the system is located at a distance d:

d = 7.33*R - 5*R = 2.33 R

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3 years ago

A 0.72-m long string has a mass of 4.2 g. The string is under a tension of 84.1 N. What is the speed of a wave on this string?

frosja888 [35]

The speed of the wave in the string is 83.4 m/s

Explanation:

For a standing wave in a string, the speed of the wave is given by the equation:

$v=\frac{1}{2L}\sqrt{\frac{T}{m/L}}$