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3 years ago

What is the potential energy of a 20-kg safe sitting on a shelf 0.5 meters

Physics

1 answer:

ki77a [65]3 years ago

8 0

Explanation:

P.E=MGH

Where m is mass

Where G is Acceleration Due to Gravity

Where h is Height

So the parameters are M = 20kg

G = 9.8m/s

H = 0.5meters

P.E= 20x9.8x0.5

=98J.

So Ans. is A= 98J

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A girl playing tug-of-war with her dog pulls the dog a distance of 8.0m by exerting a force at an angle of 18° with the horizont

AnnZ [28]

Answer:

25 N

Explanation:

Work is a product of force and perpendicular distance moved.

W=Fd where F is force exerted and d is perpendicular distance.

However, for this case, the distance is inclined hence resolving it to perpendicular so that it be along x-axis we have distance as $dcos\theta$

Therefore, $W=Fdcos\theta$

Making F the subject of the formula then

$F=\frac {W}{dcos\theta}$ where $\theta$ is the angle of inclination. Substituting 190 J for W then 18 degrees for $\theta$ and 8 m for d then

$F=\frac {190}{8cos18^{\circ}}\approx 25N$

3 0

2 years ago

Will mark as brainliest if correct!!!!!!!!!!!

Aneli [31]

Answer:

The answer is A.

Explanation:

The diagram shows the light ray bending away from the normal. Light rays bend away from the normal when their speed increases. This means that in the diagram, the light ray moves from a medium in which light has a lower speed to a medium in light has a higher speed. The only choice where the speed of light increases from A to B is answer A. So that has to be the answer.

7 0

3 years ago

Show that the electric potential along the axis of a uniformly charged disk of radius R and charge density sigma is given by by

OlgaM077 [116]

Explanation:

Area of ring $\ 2{\pi} a d a$

Charge of on ring $d q=-(\ 2{\pi} a d a)$

Charge on disk

$Q=-\left(\pi R^{2}\right)$

$\begin{aligned}d v &=\frac{k d q}{\sqrt{x^{2}+a^{2}}} \\&=2 \pi-k \frac{a d a}{\sqrt{x^{2}+a^{2}}} \\v(1) &=2 \pi c k \int_{0}^{R} \frac{a d a}{\sqrt{x^{2}+a^{2}}} \cdot_{2 \varepsilon_{0}}^{2} R \\&=2 \pi \sigma k[\sqrt{x^{2}+a^{2}}]_{0}^{2} \\&=\frac{2 \pi \sigma}{4 \pi \varepsilon_{0}}[\sqrt{z^{2}+R^{2}}-(21)] \\&=\frac{\sigma}{2}(\sqrt{2^{2}+R^{2}}-2)\end{aligned}$

Note: Refer the image attached

8 0

3 years ago

Una cuerda de 20 pies se estira entre dos arboles. Un peso W cuelga del centro de la cuerda hace que el punto medio de la misma

Galina-37 [17]

Answer:

La magnitud de la masa del peso es 78.447 libras-masa.

Explanation:

La tensión es una fuerza de reacción de la cuerda causada por la acción de una fuerza externa. En este caso, esa fuerza externa es el peso que cuelga en el centro de la cuerda. Abajo hemos adjuntado una representación simplificada del enunciado.

Por las leyes de Newton, tenemos la siguiente ecuación de equilibrio conformada por tres fuerzas:

$\vec T_{1} + \vec T_{2} + \vec W = (0, 0)\, [N]$ (1)

Donde:

$\vec T_{1}$ , $\vec T_{2}$ - Tensiones a cada lado de la cuerda, en newtons.

$\vec W$ - Peso, en newtons.

Si sabemos que $\vec T_{1} = T\cdot (\cos \alpha, \sin \alpha)$ , $\vec T_{2} = T\cdot (-\cos \alpha, \sin \alpha)$ y $\vec W = W\cdot (0, -1)$ , entonces tenemos la siguiente ecuación vectorial:

$T\cdot (\cos \alpha, \sin \alpha) + T\cdot (-\cos\alpha, \sin \alpha) + W\cdot (0, -1) = (0,0)$

$T\cdot (0, 2\cdot \sin \alpha) = W\cdot (0, 1)$

Esto permite reducir la anterior expresión a una fórmula escalar:

$2\cdot T\cdot \sin \alpha = W$

Donde $\alpha$ es el ángulo de inclinación de la cuerda, medido en grados sexagesimales.

El ángulo de inclinación de la cuerda se determina mediante la siguiente fórmula trigonométrica inversa es:

$\alpha = \tan^{-1} \left(\frac{2\,ft}{10\,ft}\right)$

$\alpha \approx 11.310^{\circ}$

Si conocemos que $\alpha \approx 11.310^{\circ}$ y $T = 200\,lbf$ , entonces la magnitud del peso es:

$W = 2\cdot (200\,lb)\cdot \sin 11.310^{\circ}$

$W \approx 78.447\,lbf$

En el Sistema Imperial, las fuerzas son medidas en forma gravitacional, entonces la magnitud de la fuerza gravitacional del peso equivale a la magnitud de su masa. En síntesis, la magnitud de la masa es $78.447\,lbm$ .

La magnitud de la masa del peso es 78.447 libras-masa.

7 0

2 years ago

A ball travels with velocity given by Error converting from MathML to accessible text., with wind blowing in the direction given

KengaRu [80]

Answer: The magnitude of the velocity = 2/5 m/s

Explanation:

In this question, the magnitude of the velocity is the product of the magnitude of the displacement vector and the magnitude of the component of the velocity that acts in the direction of displacement.

This will be a scalar projection of V onto X

Please find the attached files for the solution

5 0

3 years ago