Please help me question 8

An infrared (IR) and ultraviolet (UV) wave propagating through a vacuum must have the same____

Zinaida [17]

Answer:

D. Wavelength

Explanation:

An infrared (IR) and ultraviolet (UV) wave propagating through a vacuum must have the same wavelength.

3 0

2 years ago

In 1995 a research group led by Eric Cornell and Carl Wiemann at the University of Colorado successfully cooled Rubidium atoms t

saveliy_v [14]

Answer:

0.00493 m/s

Explanation:

T = Temperature of the isotope = 85 nK

R = Gas constant = 8.341 J/mol K

M = Molar mass of isotope = 86.91 g/mol

Root Mean Square speed is given by

$v_r=\sqrt{\dfrac{3RT}{M}}\\\Rightarrow v_r=\sqrt{\dfrac{3\times 8.314\times 85\times 10^{-9}}{86.91\times 10^{-3}}}\\\Rightarrow v_r=0.00493\ m/s$

The Root Mean Square speed is 0.00493 m/s

6 0

3 years ago

If a child starts from rest at point A and lands in the water at point B, a horizontal distance L = 2.52 m from the base of the

tamaranim1 [39]

Answer:

The height of the water slide is 0.878 m

Explanation:

Given that,

Distance = 2.52 m

Suppose Children slide down a friction less water slide that ends at a height of 1.80 m above the pool.

We need to calculate the time

Using equation of motion

$s=ut+\dfrac{1}{2}gt^2$

Put the value in the equation

$1.80=0+\dfrac{1}{2}\times9.8\times t^2$

$t^2=\dfrac{1.80\times2}{9.8}$

$t=\sqrt{\dfrac{1.80\times2}{9.8}}$

$t=0.606\ sec$

We need to calculate the velocity

Using formula of velocity

$v = \dfrac{d}{t}$

Put the value into the formula

$v=\dfrac{2.52}{0.606}$

$v=4.15\ m/s$

We need to calculate height

Using conservation of energy

$\dfrac{1}{2}mv^2=mgh$

$h=\dfrac{v^2}{2g}$

Put the value into the formula

$h=\dfrac{4.15^2}{2\times9.8}$

$h=0.878\ m$

Hence, The height of the water slide is 0.878 m.

4 0

2 years ago

If there are 50 people per square kilometer in a city, and the area of the city is 1.5 × 10 square kilometers. What is the total

qaws [65]

Answer:

750 people

Explanation:

From the question,

Number of people in the city = population density×Area of the city

N = D×A.......................... Equagtion 1

Where N = Number of people in the city, D = population density, A = Area of the city.

Given: D = 50 people per square kilometer, A = 1.5×10 square kilometer.

Substitute into equation 1

N = 50(1.5×10)

N = 750 people.

Hence the total number of people in the city is 750 people.

6 0

3 years ago

A sound wave has a speed of 330m/s and a wavelength of 0.372 m. what is the frequency of the wave?

Alja [10]

Answer:

887.1Hz

Explanation:

Given parameters:

Speed of sound wave = 330m/s

Wavelength = 0.372m

Unknown:

Frequency = ?

Solution:

To solve this problem, we use the expression below:

Speed = Frequency x wavelength

330 = Frequency x 0.372

Frequency = 887.1Hz

5 0

2 years ago