Suppose you push on a heavy crate, but not hard enough to make it slide. Does a friction force act on the crate?
a.No, the friction force doesn't act.
b.Yes, opposite to your push, just enough so that F = 0.

Answer:

bias refers to effects that a conclusion that may be incorrect, as for example when a researcher patient knows what treatment is being given, to avoid bias a blinded study may be done

Explanation:

e = ?

work output = 300 J

work input = 600 J

[tex]efficiency \: = \frac{work \: output}{work \: input} \times 100[/tex]

we multiply by 100 in order to get your efficiency in percentage

[tex]e = \frac{300}{600} \times 100[/tex]

[tex]e = \frac{1}{2} \times 100[/tex]

[tex]e = 50\%[/tex]

I this helped pls give brainliest

Answer:

Explanation:

Let's go through each one.

short-wavelength - not all of them got short wavelengths.

stream of photons - yup, they all got a stream of photons, but the longer wavelengths' photons don't carry much energy such as the shorter wavelengths.

energy in atoms - yes, all wavelengths have energy, the short wavelengths carry more energy than the longer ones.

only from radioactive material - not at all. Radio waves and microwaves are not radioactive! only the wavelengths that carry a large amount of energy are radioactive - these are the shorter wavelengths - these might be gamma rays and x-rays.

speed of 300,000 kilometers per second - yes! all electromagnetic radiation travels at this speed! isn't it amazing?

travel through vacuum of space - yup, all of them.

Hope this helps!

3 options to help Alana achieve her goals include;

For Alana to save a considerable amount of her money, she must be willing to draw a priority list where important expenses come first. Expenses that are not so important can come later.

When she receives her salary, the money for expenses should be immediately separated from the savings. Alana's note shows that she spends a lot on entertainment. $40 on coffee, $36 on movies, $48 on meals with friends, 3 trips to the mall are way too much on entertainment. Alana should reduce the expenditures on pleasures.

If Alana decides to work more, she might break down in her physical health but if she decides to adjust her budget, then she saves her energy and invests more time in her studies.

Summarily, for Alana to achieve her goals, she should make a list, separate money for expenses, and cut down on entertainment.

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Explanation:

velocity = frequency × wave length

33 = 22 × wave length

wave length = 33 ÷ 22 = 1.5 m

this is the correct answer Step-by-step

I hope you understand...

can you please mark my answer

Answer:

C

Explanation:

EDGE22

Answer:

a,this help to know the

period in which an element belong to,which also talks about the oxidation number or state of this uncombined element

[tex]\Large \boxed{\displaystyle density \ (kgm^{-3})=\frac{mass\ (kg)}{volume \ (m^3)} }[/tex]

Explanation:

u (initial velocity) = 0

acceleration = 2.5 m/s²

s (distance) = 100 m

Then,

v² = u² + 2as

v² = (0)² + 2×2.5×100

v² = 0 + 500

v² = 500

v = √500

v = 10√5 m/s

When a car starts from rest and accelerates at a constant rate of 2.5 m/s2 then the car's velocity after the car has traveled 100 m would be 15.81 m/s.

The rate of change of the velocity with respect to time is known as the acceleration of the object.

As given in the problem a car starts from rest and accelerates at a constant rate of 2.5 m/s2 then we have to find the car's velocity after the car has traveled 100 m.

By using the third equation of motion

v² - u² = 2×a×s

By substituting the respective values in the equation, as given the car cover a distance of 100 m

v² - u² = 2×a×s

v²-0² =2× 2.5×50

v²=250

v = 15.81 m/s

Thus, the car's velocity would be 15.81 m/s.

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Answer:

10 kg-m/s

Explanation:

It is given that,

Before the collision, each car (red+yellow) had a momentum of 5 kg.m/s.

After the collision, the yellow car now has a momentum of 0.

We need to find the momentum of the red car after the collision. The conservation of momentum will be applied in this problem. A/c to this law,

Momentum before collision = Momentum after collision

[tex]p_r+p_y=p'_r+p'_y[/tex]

[tex]5+5=0+p'_r\\\\p'_r=10\ kg-m/s[/tex]

Hence, the momentum of the red car after the collision is 10 kg-m/s.

Answer:

International Environmental Problems require international Cooperation to resolve them Factors Responsible for the Emergence of the Environment as a Global Issue 1. The Multiplication and Deepening of Environmental Problems.

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Answer:

21.76J

Explanation:

F=ma

where:

m=mass

a=acceleration

Kamaria's mother should pull her with a force of  21.76 Newton if she (Kamaria) wants her acceleration to be 0.80 m/s².

In order to accelerate a body of mass 'm kg' with an acceleration of 'a m/s²', a force of magnitude equal to the product of mass and required acceleration is required. Mathematically -

F = m x a

Given is a girl learning how to ice skate. She wants to move with an acceleration of 0.80 m/s² and her mass is 27.2 kg.

From the definition of force, we can write -

F = m x a

F = 27.2 x 0.8

F = 21.76 Newton

Therefore, Kamaria's mother should pull her with a force of  21.76 Newton if she (Kamaria) wants her acceleration to be 0.80 m/s²

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Explanation:

K.E = 5,000,000 KJ

MASS = 100,000,000 Kg

K.E = 1/2 MV^2

[tex]5000000 = \frac{1}{2} \times 100000000 \times v {}^{2} [/tex]

[tex]5000000 = 50000000 \times v {}^{2} [/tex]

[tex]v {}^{2} = \frac{5000000}{50000000} [/tex]

[tex]v {}^{2} = \frac{5}{50} [/tex]

therefore

[tex]v {}^{2} = \frac{1}{10} [/tex]

[tex]v = \sqrt{0.1} [/tex]

v = 0.316 m/s^2

The velocity of the cruise ship whose mass is 10⁸ Kg moving with Kinetic energy of 5 x 10⁹J is 10 m/s

The Kinetic energy of the body is the energy possessed by body by virtue of its motion.

Given is a cruise ship that has a mass of 100,000,000 kg and has a kinetic energy of 5,000,000 kJ. From this, we can write -

Mass [M] = 10⁸ Kg

Energy [E] = 5 x 10⁶ KJ = 5 x 10⁹ J

The formula to calculate the Kinetic energy of the body is -

E [K] = E = 1/2 mv²

v² = 2E/m

v² = (2 x 5 x 10⁹)/10⁸

v² = 100

v = √100

v = 10 m/s

Therefore, the velocity of the cruise ship whose mass is 10⁸ Kg moving with Kinetic energy of 5 x 10⁹J is 10 m/s

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Answer:

D: A kitten gains weight.

Explanation:

Answer:

distance = 6.1022 x10^16[m]

Explanation:

To solve this problem we must use the formula of the average speed which relates distance to time, so we have

v = distance / time

where:

v = velocity = 3 x 10^8 [m/s]

distance = x [meters]

time = 6.45 [light years]

Now we have to convert from light-years to seconds in order to get the distance in meters.

[tex]t = 6.45 [light-years]*365[\frac{days}{1light-year}]*24[\frac{hr}{1day}] *60[\frac{min}{1hr}]*60[\frac{seg}{1min} ] =203407200 [s][/tex]

Now using the formula:

distance = v * time

distance = (3*10^8)*203407200

distance = 6.1022 x10^16[m]

Answer:

Drawing Bohr Models

1. Draw the nucleus.

2. Write the number of Protons and  Neutrons in the nucleus

3. Draw the first shell

4. Add the electrons, the first shell  can only hold 2

5. Draw the next shell if you  have more electrons to add

6. Add your electrons, the 2nd  shell can hold up to 8

7. Check yours Valence  electrons

Explanation:

Answer:

When a car stops suddenly, we fall forwards. This is because the upper part of our body tends to continue to be in motion due to inertia. Newton's first law of motion, sometimes referred to as the law of inertia, states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. When the car stops slowly, its force is lesser than when the car stops harshly. This act of unbalanced force makes the mangoes fly forward.

Explanation:

I hope this helps!

Answer:

by finding melting and boiling points

Explanation:

Answer:

Simple chemical tests can be used to identify the presence of various elements or classes of molecules (Tollen's test). ... Electron spin resonance (ESR): Also referred to as electron paramagnetic resonance (EPR), this method uses the spins of unpaired electrons in molecules to determine structure

Answer:

μ = .4842

Explanation:

Assuming constant acceleration and the object is sliding on a level surface:

Let's start off by finding the acceleration of the object.

v² = v₀² + 2aΔx

Now, we can make a free-body diagram and see that the only force opposing the object's motion is the friction force -- this is the only force in the x-direction.

We can use Newton's 2nd Law: F = ma to solve for the coefficient of friction.

F = ma

Now, we have:

The mass cancels out and solving for the coefficient of friction gives us:

We know the acceleration is -4.75 m/s² and g = -9.81 m/s²:

The coefficient of kinetic friction between the surfaces, assuming constant acceleration and a flat surface, is 0.4842.

Answer:

When 1 Joule of work is done to move a charge of amount 1 Coulomb from one place to another, then it is said that the potential difference between the two points is 1 Volt (V)

Answer:

2. an explanation of that natural world that has been repeatedly confirmed through observation and experimentation and is accepted by the scientific community.

Answer:

it will sink because object that have less they float not more

Answer:

it will sink here's why

Explanation: The density of an object determines whether it will float or sink in another substance. An object will float if it is less dense than the liquid it is placed in. An object will sink if it is more dense than the liquid it is placed in.

Answer:

elastic potential energy

Explanation:

The situation above shows an example of an "elastic potential energy." This type of potential energy depends on the force being applied to the elastic object.

In the situation above, the elastic object is the rubber band. The resultant energy is then being stored until such time that this object will be freed. Once this happens, the elastic object will revert to its original form and the rock will soar (be released).

The amount of energy that is being stored largely depends on the distance of the "stretch" being applied to the object. It is said that the greater the force, the greater the stretch and the greater the distance covered by the rock (and vice-versa).

Answer:

In order to catch the box before it hits the ground, the person needs to go as fast as approximately 5.96 m/s

Explanation:

The height of the hot air balloon above the ground, s = 92.4 m

The location on the ground of the person intending to catch the box, x = 10 m away horizontally from the base location of the balloon

The time it takes the balloon released at zero vertical velocity is given by the following equation;

s = 1/2·g·t²

92.4 = 1/2 × 9.8 × t² = 19.6·t²

t² = 92.4/19.6 ≈ 4.714

t = √4.714 ≈ 1.68 seconds

The time, t, it takes the box to hit the ground ≈ 1.68 seconds

The speed, v, of the person standing 10 m away has to go to catch the box before it hits the ground is v = Distance/time =10/1.68 ≈ 5.96 m/s

In order to catch the box before it hits the ground, the person needs to go as fast as approximately 5.96 m/s.

Answer:

75.5 kg

Explanation:

w=mg

755= m × 10

m = 75.5

Answer:

Their deceleration is - 19 [tex]\frac{m}{s^{2} }[/tex]

Explanation:

Acceleration is a quantity that indicates how the speed of the object changes over time. In other words, acceleration is a vector quantity that relates changes in velocity to the time it takes to occur. It is normally represented by the letter a and its unit of measurement, in the International System it is meters per second squared [tex]\frac{m}{s^{2} }[/tex].

The mathematical expression for the acceleration is:

[tex]a=\frac{final speed - initial speed}{final instant - initial instant}[/tex]

In this case:

Replacing:

[tex]a=\frac{0 \frac{m}{s} - 2.8\frac{m}{s} }{0.15 s - 0s}[/tex]

a= -18. 667 [tex]\frac{m}{s^{2} }[/tex] ≅ -19 [tex]\frac{m}{s^{2} }[/tex]

Deceleration is a quantity that expresses the passage of a moving body from one speed to a lower speed. Mathematically it is calculated as the acceleration but the result will be a negative acceleration.

Their deceleration is - 19 [tex]\frac{m}{s^{2} }[/tex]

Option 1,3 and 5 are correct. Work is defined as the product of applied force and the distance through which the body is displaced on which the force is applied.

Work is defined as the product of applied force and the distance through which the body is displaced on which the force is applied.

Work may be zero, positive or negative.it depends on the direction of the body displaced. if the body is displaced in the same direction of the force it will be positive .

while if the displacement is in the opposite direction of force applied the work will be negative work. if there is no displacement of the body the work done will be zero.

The following options are correct because the work is due to displacement. In all three options, the displacement is done. The correct options are;

A cat lifts up her kitten by its neck.

A bird flies a worm from the ground to its nest in a tree.

A horse pulls a wagon along a road.

Hence options 1,3 and 5 are correct.

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Answer:

its 1, 3, and 5

Explanation:

or a, c, and e

Answer: metals

Explanation: