un hombre intenta levantar una caja de 5 kg sobre una mesa aplicando una fuerza vertical de 10 N. ¿En esta situacion, el valor d

A 15.0 cm object is 12.0 cm from a concave mirror that has a focal length of 4.8 cm. Its image is 8.0 cm in front of the mirror.

kicyunya [3294]

The correct answer is -10.

7 0

1 month ago

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Two vectors A⃗ and B⃗ are at right angles to each other. The magnitude of A⃗ is 4.00. What should be the length of B⃗ so that th

serg [3582]

Answer:

B= $\sqrt{65}$ ≅8.06

Explanation:

Applying the Pythagorean theorem:

$C^{2}$ = $A^{2}$ + $B^{2}$

Here, C denotes the hypotenuse length, while A and B signify the lengths of the other two sides of the triangle. We can calculate B's length knowing the hypotenuse is 9 and A is 4.

$9^{2}$ = $4^{2}$ + $B^{2}$

81= 16+ $B^{2}$

81-16= $B^{2}$

B= $\sqrt{65}$ ≅8.06

8 0

3 months ago

A block of mass m, initially held at rest on a frictionless ramp a vertical distance H above the floor, slides down the ramp and

kicyunya [3294]

Answer:

$\displaystyle W=-m.g.H$

Explanation:

Transformation of Energy

Also known as energy conversion, this refers to the process in which energy shifts from one type to another. In this context, three energy forms are involved. When the object is stationary at the ramp's peak, it possesses gravitational potential energy, calculated as

$U=m.g.H$

As the object descends the frictionless ramp, it converts all its potential energy into kinetic energy, represented as

$\displaystyle K=\frac{m.v^2}{2}$

Thus,

$K=m.g.H$

Ultimately, when the object encounters a rough surface, all energy converts to thermal energy. The work performed by the friction force corresponds to the alteration in kinetic energy, as all velocity is lost in this process:

$\displaystyle W=\Delta E=K_f-K=0-K=-\frac{m.v^2}{2}$

Given the kinetic energy equals the initial potential energy:

$\boxed{\displaystyle W=-m.g.H}$

The negative sign indicates that the work acted against the direction of movement, meaning the force and displacement are 180° apart.

This outcome is independent of the distance D needed to halt the block or the kinetic friction coefficient.

7 0

3 months ago

The human eye can respond to as little as 10^−18 J of light energy. For a wavelength at the peak of visual sensitivity, 550 nm,

Yuliya22 [3333]

The fundamental equation is derived from Mr. Planck: E=h \nu, where h is Planck’s constant and ν is the frequency. This relationship describes the energy per photon at a specific frequency. Although a wavelength is provided, it can easily be converted to frequency using the equation: c= lambda / nu, where c denotes the speed of light; λ (lambda) is the wavelength; and ν is the frequency. Once the energy of a photon with a wavelength of 550nm is determined, it will show how many photons are needed to gather 10^-18J. Remember to pay attention to the units.

7 0

1 month ago

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A specimen of steel has a rectangular cross section 20 mm wide and 40 mm thick, an elastic modulus of 207 GPa, and a Poisson’s r

Softa [3030]

Response: The width decreases by 2.18 × 10^(-6) m

Clarification:

Given data;

Shear Modulus; E = 207 GPa = 207 × 10^(9) N/m²

Force; F = 60000 N.

Poisson’s ratio; υ = 0.30

The initial width is 20 mm, and the thickness is 40 mm.

Area = 20 × 10^(-3) × 40 × 10^(-3)

Area = 8 × 10^(-4) m²

The formula for shear modulus is;

E = σ/ε_z

where σ represents stress calculated as Force(F)/Area(A)

while ε_z stands for longitudinal strain.

Thus;

E = (F/A)/ε_z

ε_z = (F/A)/E

ε_z = (60,000/(8 × 10^(-4)))/(207 × 10^(9))

ε_z = 3.62 × 10^(-4)

Next, the lateral strain is given by;

ε_x = - υ × ε_z

ε_x = -0.3 × 3.62 × 10^(-4)

ε_x = -1.09 × 10^(-4)

The change in width can be determined as;

Δw = w_o × ε_x

Where w_o denotes the original width = 20 × 10^(-3) m

So; Δw = 20 × 10^(-3) × -1.09 × 10^(-4)

Δw = -2.18 × 10^(-6) m

A negative sign indicates a reduction in width.

Therefore, the width decreases by 2.18 × 10^(-6) m

6 0

2 months ago