What is the definition of acceleration

A biconvex lens is formed by using a piece of plastic(n=1.70).

creativ13 [48]

Answer:

$f =17.15\ cm$

Explanation:

given,

refractive index of lens, n = 1.70

Radius of curvature of front surface. R₁ = 20 cm

Radius of curvature of the back surface, R₂ = 30 cm

focal length= ?

$\dfrac{1}{f}=(n-1)(\dfrac{1}{R_1}-\dfrac{1}{R_2})$

R₁ = +20 cm

R₂ = -30 cm

n = 1.70

$\dfrac{1}{f}=(1.70-1)(\dfrac{1}{20}-\dfrac{1}{-30})$

$\dfrac{1}{f}=0.70 \times 0.0833$

$f = \dfrac{1}{0.7 \times 0.0833}$

$f =17.15\ cm$

the focal length of the lens is equal to 17.15 cm

3 0

2 years ago

Two neutron stars are separated by a distance of 1.0 x 1012 m. They each have a mass of 1.0 x 1028 kg and a radius of 1.0 x 103

son4ous [18]

To develop this problem it is necessary to apply the concepts related to Gravitational Potential Energy.

Gravitational potential energy can be defined as

$PE = -\frac{GMm}{R}$

As M=m, then

$PE = -\frac{Gm^2}{R}$

Where,

m = Mass

G =Gravitational Universal Constant

R = Distance /Radius

PART A) As half its initial value is u'=2u, then

$U = -\frac{2Gm^2}{R}$

$dU = -\frac{2Gm^2}{R}$

$dKE = -dU$

Therefore replacing we have that,

$\frac{1}{2}mv^2 =\frac{Gm^2}{2R}$

Re-arrange to find v,

$v= \sqrt{\frac{Gm}{R}}$

$v = \sqrt{\frac{6.67*10^{-11}*1*10^{28}}{1*10^{12}}}$

$v = 816.7m/s$

Therefore the velocity when the separation has decreased to one-half its initial value is 816m/s

PART B) With a final separation distance of 2r, we have that

$2r = 2*10^3m$

Therefore

$dU = Gm^2(\frac{1}{R}-\frac{1}{2r})$

$v = \sqrt{Gm(\frac{1}{2r}-\frac{1}{R})}$

$v = \sqrt{6.67*10^{-11}*10^{28}(\frac{1}{2*10^3}-\frac{1}{10^{12}})}$

$v = 1.83*10^7m/s$

Therefore the velocity when they are about to collide is $1.83*10^7m/s$

7 0

2 years ago

Which statement best describes air pressure at high altitudes? (Points : 3)

WARRIOR [948]

Air pressure decreases as altitude increases. this is because air pressure is caused by the gravity of earth, the gravity pulls on the air, compacting it and making a pressure.
But as we go higher, gravity decreases, causing less pull on the air resulting in less air pressure.<span />

5 0

2 years ago

Read 2 more answers

Que unidad de medida se utiliza para expresar la capacidad o volumen de un objeto? Da un ejemplo

galina1969 [7]

Answer:

<em>Explicado a continuación</em>

Explanation:

Hay una pequeña diferencia conceptual entre la capacidad y el volumen de un objeto, a saber:

El volumen hace referencia al espacio que ocupa un objeto, mientras que la capacidad hace referencia al espacio que este contiene. Calcular el volumen de un cuerpo es medir cuánto ocupa mientras que calcular su capacidad es medir cuánto cabe en él.

En la práctica, ambos conceptos son usados indistintamente, ya que tienen unidades equivalentes.

El volumen tiene unidades de longitud al cubo, como por ejemplo:

$m^3,\ cm^3\ ,dm^3,\ pie^3\ , pulg^3$

y la capacidad se suele expresar en litros o unidades derivadas: litro, mililitro, centilitro, etc.

Como mencionamos, hay equivalencia engre los dos grupos de unidades. Entre las más conocidas están:

$1\ lt=1\ dm^3,\ 1\ m^3=1000\ lt$

5 0

2 years ago

an acorn falls from a tree. ignoring air resistance, what forces are on the acorn while it’s falling?

Triss [41]

Answer: gravity

Explanation:

4 0

1 year ago