Please please help me please please help please please

Pedro needs to control the variables such as volume of water and temperature during his experiment. So, option C.

The amount of water vapor in the air is known as humidity. The humidity will be high if there is a lot of water vapour in the atmosphere.

Water can evaporate even at very low temperatures, but as the temperature rises, the rate of evaporation increases.

More surface molecules per unit of volume may be able to escape from a substance with a larger surface area, so it will evaporate more quickly.

The control variables in an experiment are the variables that the experimenter intends to keep constant always so as to limit their effect on the measurements of the relationship between the dependent and the independent variable.

Therefore, in order to have a proper measurement of the effect of humidity on evaporation rate, other variables such as temperature, and the volume of the water in the experiment investigations which affect evaporation rate by the provision of heat, (temperature) and their heat capacity, the volume, etc. should be controlled.

Hence,

Pedro needs to control the variables such as volume of water and temperature during his experiment. So, option C.

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Answer:

[tex]56.5\ \text{s}[/tex]

[tex]21.13\ \text{m/s}[/tex]

Explanation:

v = Final velocity

u = Initial velocity

a = Acceleration

t = Time

s = Displacement

Here the kinematic equations of motion are used

[tex]v=u+at\\\Rightarrow t=\dfrac{v-u}{a}\\\Rightarrow t=\dfrac{25-0}{2}\\\Rightarrow t=12.5\ \text{s}[/tex]

Time the car is at constant velocity is 39 s

Time the car is decelerating is 5 s

Total time the car is in motion is [tex]12.5+39+5=56.5\ \text{s}[/tex]

Distance traveled

[tex]v^2-u^2=2as\\\Rightarrow s=\dfrac{v^2-u^2}{2a}\\\Rightarrow s=\dfrac{25^2-0}{2\times 2}\\\Rightarrow s=156.25\ \text{m}[/tex]

[tex]s=vt\\\Rightarrow s=25\times 39\\\Rightarrow s=975\ \text{m}[/tex]

[tex]v=u+at\\\Rightarrow a=\dfrac{v-u}{t}\\\Rightarrow a=\dfrac{0-25}{5}\\\Rightarrow a=-5\ \text{m/s}^2[/tex]

[tex]s=\dfrac{v^2-u^2}{2a}\\\Rightarrow s=\dfrac{0-25^2}{2\times -5}\\\Rightarrow s=62.5\ \text{m}[/tex]

The total displacement of the car is [tex]156.25+975+62.5=1193.75\ \text{m}[/tex]

Average velocity is given by

[tex]\dfrac{\text{Total displacement}}{\text{Total time}}=\dfrac{1193.75}{56.5}=21.13\ \text{m/s}[/tex]

The average velocity of the car is [tex]21.13\ \text{m/s}[/tex].

Complete Question

A 10 kg medicine ball is thrown at a velocity of 15 km/hr ( m/s) to a 50 kg skater who is at rest on the ice. The skater catches the ball and subsequently slides with the ball across the  ice.

Calculate the kinetic energy after collision(in joules).

Answer:

 [tex]K.E=70.23J[/tex]

Explanation:

From the question we are told that:

Mass of ball [tex]m_b=10kg[/tex]

Speed [tex]V_{b1}=15 km/hr ( m/s)[/tex]

            [tex]V_{b1} = 4.1667 m/s[/tex]

            [tex]V_{b1} = 4.1667 m/s[/tex]

Mass of Skater [tex]m_s=50kg[/tex]

Generally the equation for conservation of momentum is mathematically given by

  [tex]m_sV_{s1}+m_bV_{b1}=(m_s+m_b)V[/tex]

  [tex]V=\frac{m_sV_{s1}+m_bV_{b1}}{(m_s+m_b)}[/tex]

  [tex]V=\frac {50+10*4.1667}{(50+10)}[/tex]

  [tex]V=1.53m/s[/tex]

Generally the equation for  Kinetic energy is mathematically given by

 [tex]K.E=\frac{1}{2}(m_s+m_b)V^2[/tex]

 [tex]K.E=\frac{1}{2}(50+10)(1.53)^2[/tex]

 [tex]K.E=70.23J[/tex]

Therefore kinetic energy K.E after collision is given as

 [tex]K.E=70.23J[/tex]

Answer: Frequency

Explanation: Frequency is term which best describes how often a person exercises.

Answer:

frequency

Explanation:

I took the. test

Answer:

The final angular velocity is rev/s is 0.293 rev/s.

Explanation:

Given;

mass of the merry-go-round, m₁ = 120 kg

radius of the merry-go-round, r = 1.8 m

initial angular velocity, ω = 0.4 rev/s

mass of the child, m₂ = 22 kg

Apply the principle of conservation angular momentum to determine the final angular velocity;

[tex]I_i= I_f\\\\\frac{1}{2} m_1r^2 \omega _i = \frac{1}{2} m_1r^2 \omega _f + m_2r^2 \omega _f\\\\ \frac{1}{2} m_1r^2 \omega _i =( \frac{1}{2} m_1r^2 + m_2r^2 )\omega _f\\\\\omega _f = \frac{ \frac{1}{2} m_1r^2 \omega _i}{\frac{1}{2} m_1r^2 + m_2r^2} \\\\\omega _f = \frac{ \frac{1}{2} m_1 \omega _i}{\frac{1}{2} m_1 + m_2}\\\\\omega _f = \frac{0.5 \ \times \ 120\ kg \ \times \ 0.4\ rev/s}{0.5 \ \times 120\ kg \ \ + \ \ 22 \ kg} \\\\\omega _f = 0.293 \ rev/s\\[/tex]

Therefore, the final angular velocity is rev/s is 0.293 rev/s.

Answer: It takes 12 N of force to pull the wagon.

Explanation:

2 bar magnets top to bottom with their long axes vertical, the top one with red S on top and blue N on bottom and the bottom magnet with red S on top and blue N on bottom. this diagram shows magnets that will attract each other. Hence option D is correct.

A permanent magnet is an item constructed of magnetised material that generates its own persistent magnetic field. A refrigerator magnet, for example, is commonly used to hold notes on a refrigerator door. Ferromagnetic (or ferrimagnetic) materials are those that can be magnetised and are strongly attracted to a magnet. These include the elements iron, nickel, and cobalt, as well as their alloys, some rare-earth metal alloys, and naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones that are strongly attracted to a magnet and are widely thought to be magnetic, all other substances respond weakly to a magnetic field via one of many different forms of magnetism.

Hence option D is correct.

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Answer:

d. the voltage difference between the ends of each resistor is the same.

Explanation:

A resistor is a circuit component that offers opposition to the flow of current. Resistors may be connected in series or in parallel.

Resistors in parallel are connected at common junctions. The potential difference (voltage difference between the ends of each resistor) is the same for each resistor in a parallel connection while the current across each resistor is different.

Answer:

The balloon will collapse

Explanation:

When air is removed from the bell jar, the balloon will collapse if the internal pressure from the balloon does not balance the atmospheric pressure from the surroundings.

Answer:

https://www.slader.com/discussion/question/an-electron-is-accelerated-through-240-times-103-v-from-rest-and-then-enters-a-uniform-170-t-magnetic-field-what-are-a-the-maximum-and-b-the-9e425fbd/

( Here is solution)

Answer:

The answer is B

Explanation:

The absorption happens when photons from light hit atoms and molecules, and they vibrate because of that specific interaction. Then the heat ejects from the object in the format of thermal energy.

For an object to appear transparent, light waves must be transmitted through the object. Option D is correct.

Light waves are a type of electromagnetic radiation that can be perceived by the human eye.

Here,
For an object to appear transparent, light waves must be transmitted through the object. Therefore, the correct answer is D. When light waves are transmitted, they pass through the object without being absorbed or reflected, allowing us to see through the object. The degree to which light is transmitted through an object is related to the object's optical properties, such as its refractive index, which determines how much the light is bent as it passes through the object.

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For the  pendulum taken to the moon, The frequency change that would occur is mathematically given as

[tex]\frac{Fmoon}{Fearth}=0.408[/tex]

Generally, the equation for the Time period  is mathematically given as

[tex]T=2\pi\sqrt{L/g}[/tex]

Therefore

[tex]\frac{Fmoon}{Fearth}=\frac{\sqrt{g/6L}}{\sqrt{g/6L}}\\\\\frac{Fmoon}{Fearth}=\sqrt{1/6}[/tex]

[tex]\frac{Fmoon}{Fearth}=0.408[/tex]

In conclusion, The frequency change

[tex]\frac{Fmoon}{Fearth}=0.408[/tex]

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Answer:

.408

Explanation:

Answer: 10,500 kg m/s

Explanation: (1,000 + 50)(10)

Answer:

The correct answer is a

Explanation:

The speed of a sound wave depends on the square root of the modulus of compressibility and the density of the medium.

For the same medium, the speed of sound depends on the temperature of the fora

           v = [tex]v_o \ \sqrt{1 + \frac{T}{273} }[/tex]

Therefore, the different results that are obtained are due to changes in temperature. The correct answer is a

since this way it has the values ​​of the speed of sound for each temperature, for which it can compare with the results obtained from the trip.

Answer:

M v^2 / R = centripetal force

For Red: M v^2 / R = 5 * 9^2 / 1.5 = 270

For Blue M v^2 / R = 270 = 25 * 1.8^2 / Rb

So Rb = 25 * 1.8^2 / 270 = .3 m

Answer:

Explanation:

In equilibrium , weight of mug is equal to restoring force .

mg = kx where m is mass of mug , k is spring constant and x is extension .

k / m = g / x = 9.8 ms⁻² / .025 m

= 392

frequency of oscillation n = [tex]\frac{1}{2\pi}\sqrt{\frac{k}{m} }[/tex]

[tex]n=\frac{1}{2\pi}\sqrt{392 }[/tex]

= 4.46 per second.

Answer:

1 L = 1000 mL

125 mL = 125/1000 = 0.125 L

Answer:

0.125

Explanation:

divide by 1 000 to convert mL to liters

Answer:

The work done by you on the two cart system is 2 N-m

Explanation:

Work done is the product of force and displacement.

W = F * D

Substituting the given values we get -

W =

[tex]4 * (0.17+0.33)\\= 2[/tex]

The work done by you on the two cart system is 2 N-m

102 m

Explanation:

The time 0.6 sec is the time it took for the sound to travel from the bat to the moth and back. So it took 0.3 sec for the sound to reach the moth. From the definition of speed, the distance of the moth d to the bat is given by

v = d/t ---> d = vt = (340 m/s)(0.3 sec) = 102 m

Answer:

 θ = 35.7º

Explanation:

For this exercise we must use the law of Malus

          I = I₀ cos² θ

where the angle is between the two polarizers.

When the unpolarized light from the sun reaches the first polarizer, only the light polarized in the direction manages to be transmitted, which is why

          I₁ = I₀ /2

this light reaches the second polarizer

           I₂ = I₁ cos² θ

           I₂ = I₀/2    cos² θ

           cos² θ = 2 I₂ / Io

indicate that the transmitted light is 33% = 0.33 I₀

          cos² θ = 2 0.33

          cos θ = √0.66

          θ = cos⁻¹ 0.8124

          θ = 35.7º

Answer:

Hi how are you doing today Jasmine

Answer:

The answer is B

Explanation:

I did the USA test prep

Answer:

snell's law = sinI /sin r

refractive index = sinI /sin r

1.33= 30 /sinR

sinR= 1.33×30

sinR=39.9

The angle with the normal by which the fish appear to the fisherman is 41.68 degrees.

According to the Snell's law, the ratio of index of reflection of the different material is equal to the ratio of incident sine angle and reflective sine angle. It can be given as,

[tex]\dfrac{n_1}{n_2}=\dfrac{\sin\theta_2}{\sin\theta_1}[/tex]

Here (n₁ and n₂) are the index and reflective index and (θ₁ and θ₂) are the incident and reflected angle.

The index of refraction of air is 1. Thus, by the Snell's law,

[tex]\dfrac{1}{1.33}=\dfrac{\sin(30)}{\sin\theta_1}\\\theta_1=41.68^o[/tex]

Thus, the angle with the normal by which the fish appear to the fisherman is 41.68 degrees.

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Answer:

The tension in string will be "3.62 N".

Explanation:

The given values are:

Length of string:

l = 3 ft

or,

 = 0.9144 m

frequency,

f = 60 Hz

Weight,

= 0.096 lb

or,

= 0.0435 kgm/s²

Now,

The mass will be:

= [tex]\frac{0.0435}{9.8}[/tex]

= [tex]0.0044 \ kg[/tex]

As we know,

⇒  [tex]\lambda=\frac{2L}{n}[/tex]

On substituting the values, we get

⇒     [tex]=\frac{2\times 0.9144}{4}[/tex]

⇒     [tex]=0.4572 \ m[/tex]

or,

⇒  [tex]v=f \lambda[/tex]

⇒      [tex]=0.4572\times 60[/tex]

⇒      [tex]=27.432 \ m/s[/tex]

Now,

⇒  [tex]v=\sqrt{\frac{T}{\mu} }[/tex]

or,

⇒  [tex]T=\frac{m}{l}\times v^2[/tex]

On putting the above given values, we get

⇒      [tex]=\frac{0.0044}{0.9144}\times (27.432)^2[/tex]

⇒      [tex]=\frac{752.51\times 0.0044}{0.9144}[/tex]

⇒      [tex]=3.62 \ N[/tex]

Answer:

T = 0.01 Nm

Explanation:

First, we will calculate the angular acceleration of the disk:

[tex]2\theta\alpha = \omega_f^2-\omega_i^2[/tex]

where,

θ = angular displacement = (6.37 rev)(2π rad/1 rev) = 40.02 rad/s

α = angular acceleration = ?

ωi = initial angular speed = 10 rad/s

ωf = final angular speed = 0 rad/s

Therefore,

[tex](2)(40.02\ rad/s)\alpha = (0\ rad/s)^2-(10\ rad/s)^2[/tex]

α = -1.25 rad/s²

negative sign shows deceleration

α = 1.25 rad/s²

Now, we will calculate the moment of inertia of disk:

[tex]I = \frac{1}{2}mr^2[/tex]

where,

I = Moment of Inertia = ?

m = mass of disk = 1 kg

r = radius of disk = 0.13 m

Therefore,

[tex]I = \frac{1}{2} (1\ kg)(0.13\ m)^2[/tex]

I = 0.00845 kg.m²

Now, the torque can be given as:

T = Iα

T = (0.00845 kg.m²)(1.25 rad/s²)

T = 0.01 Nm

Answer:

frequency is approximately 11.5 µHz, or more exactly, 11.5740740e-6 Hz

Explanation:

Answer:

Biodiversity decline continues due to a rapidly expanding human population. Habitat is damaged in order to meet growing needs for agriculture, urban development, water and materials. Fish, wildlife and plants are overharvested, despite mounting evidence that many harvesting practices are unsustainable.

Answer:

.0000004

Explanation:

The mass of a brick with a volume of 0.0006 m³ and a density of 1600 kg/m³ is 0.96kg.

The mass of a substance can be calculated by multiplying the density of the substance by its volume. That is;

Mass = density × volume

According to this question, the density of brick is 1,600 kg/m3 and it has a volume of 0.0006m³. The mass is calculated as follows:

Mass = 0.0006 × 1600

Mass = 0.96kg

Therefore, the mass of a brick with a volume of 0.0006m³ and a density of 1600 kg/m³ is 0.96kg.

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Answer:

I would say d I had the same question yesterday and I got it correct so hope that helps

Answer:

 v = 220 m / s

Explanation:

This is a kinematics exercise, the expression for velocity is

          v = 25 t² - 80 t - 200

asks the velocity for time t = 6 s.

let's calculate

        v = 25 6² - 80 6 - 200

        v = 220 m / s

The velocity for the first six seconds when acceleration is zero is -44 m/s.

The velocity of an object is the rate of change displacement with time.

The velocity of the object for the first six seconds when the acceleration is zero is calculated as follows;

[tex]a = \frac{dv}{dt} \\\\a = 50t - 80\\\\0 = 50t - 80\\\\50t = 80\\\\t = 1.6 \ s[/tex]

Velocity when time = 1.6 s

[tex]v(1.6) = 25(1.6)^2 - 80(1.6) - 200\\\\v(1.6) = -264 \ m/s[/tex]

The velocity for the first six seconds when acceleration is zero.

[tex]v = v_{a =0} + v_6\\\\v = - 264 \ + 25(6)^2 - 80(6) - 200\\\\v = -44 \ m/s[/tex]

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