A car with a crashtest dummy inside travels at 40.23 m/s (90 mph) toward a stone wall during a crash test. When it strikes the wall, the car takes 0.70 s to stop. Calculate the deceleration of the car.

Answer:

Explanation:

The refractive index of sea water is more than refractive index of water . so when light passes from water to sea water or from low refractive index to high refractive index , ray of light bends towards the normal . This bending is very small because the difference in refractive index is very small.

Answer:

they both exert the same pressure

Explanation:

Pressure is the ratio of force to area. It is given as:

[tex]P=\frac{F}{A}[/tex] ,  where F is the force, P is pressure and A is area

1) For the cuboid, the area of the base placed on the ground (A) = 8 cm × 3 cm = 24 cm² = 0.0024 m². Therefore the pressure is:

[tex]P=\frac{F}{A}=\frac{60}{0.0024} =25000N/m^2=25KN/m^2[/tex]

2) For the cube, the area of the base placed on the ground (A) = 4 cm × 4 cm = 16 cm² = 0.0016 m². Therefore the pressure is:

[tex]P=\frac{F}{A}=\frac{40}{0.0016} =25000N/m^2=25KN/m^2[/tex]

Therefore, they both exert the same pressure.

Answer:

Ionic bonding.

Explanation:

According to our crude, conceptual definition, chemical bonds can form either by electron transfer between atoms or by sharing of electrons. ... When atoms lose or gain electrons, they become what are called ions. Loss of electrons leaves an atom with a net positive charge, and the atom is called a cation.

Hope this helped!

Answer:

A cloud is made up of liquid water droplets. A cloud forms when air is heated by the sun. As it rises, it slowly cools it reaches the saturation point and water condenses, forming a cloud. As long as the cloud and the air that its made of is warmer than the outside air around it, it floats!

Explanation:

A cloud is made up op liquid and water droplets.

Answer:

How are clouds made

Explanation:

When sunlight hits water it evaporates into the air and makes water droplets that we see as white fluufly clouds

Explanation:

hope this helps you

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Answer:

Explanation:

c  

Answer:

When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of theparticles determines the state of matter of thesubstance. The end result of increased molecular motion is that the object expands and takes up more space.

Answer:

idk ha ha ha

Explanation:

Answer:

yes the formula of pressure is P = F/A

Answer:

yes it is

Explanation:

Answer:

The actual work output is 1,125 kilojoules.

Explanation:

Energy efficiency is defined as the efficient use of energy. An appliance, process, or facility is energy efficient when it consumes less than the average amount of energy to perform an activity. Then, energy efficiency is the ratio between the amount of energy used in an activity and the amount expected to be carried out.

Efficiency is calculated as:

efficiency = output / input

Where output is the amount of mechanical work (in watts) or energy consumed by the process (in joules), and input (input) is the amount of work or energy that is used as input to carry out the process.

In this case:

Replacing:

0.15=output/7500 kilojoules

Solving:

Output=0.15* 7500 kilojoules

output=1,125 kilojoules

The actual work output is 1,125 kilojoules.

Answer:

Explanation:

Average speed is the change in distance of a body/object with respect to time. Speed is expressed by the expression;

Speed = [tex]\frac{change\ in\ distance}{change\ in\ time}[/tex]

speed ΔV = ΔS/Δt

ΔV = S₂-S₁/t₂-t₁

given S₂ = 50m, S₁ = 40m, t₂ = 5s, t₁ = 4s

average speed = 50-40/5-4

average speed = 10/1

average speed = 10m/s

average speed of the object is 10m/s

Answer:

They're calibrated to measure, liquids of greatest density.

Explanation:

Answer:

Approximately [tex]3.1 \times 10^4 \; \rm N[/tex] (assuming that the acceleration due to gravity is [tex]g = 9.81\; \rm kg \cdot N^{-1}[/tex].)

Explanation:

Let [tex]A_1[/tex] denote the first piston's contact area with the fluid. Let [tex]A_2[/tex] denote the second piston's contact area with the fluid.

Similarly, let [tex]F_1[/tex] and [tex]F_2[/tex] denote the size of the force on the two pistons. Since the person is placing all her weight on the first piston:

[tex]F_1 = W = m \cdot g = 50\; \rm kg \times 9.81 \; \rm kg \cdot N^{-1} =495\; \rm N[/tex].  

Since both pistons fit into cylinders, the two contact surfaces must be circles. Keep in mind that the area of a square is equal to [tex]\pi[/tex] times its radius, squared:

By Pascal's Law, the pressure on the two pistons should be the same. Pressure is the size of normal force per unit area:

[tex]\displaystyle P = \frac{F}{A}[/tex].

For the pressures on the two pistons to match:

[tex]\displaystyle \frac{F_1}{A_1} = \frac{F_2}{A_2}[/tex].

[tex]F_1[/tex], [tex]A_1[/tex], and [tex]A_2[/tex] have all been found. The question is asking for [tex]F_2[/tex]. Rearrange this equation to obtain:

[tex]\displaystyle F_2 = \frac{F_1}{A_1} \cdot A_2 = F_1 \cdot \frac{A_2}{A_1}[/tex].

Evaluate this expression to obtain the value of [tex]F_2[/tex], which represents the force on the piston with the larger diameter:

[tex]\begin{aligned}F_2 &= F_1 \cdot \frac{A_2}{A_1} \\ &= 495\; \rm N \times \frac{2.25\, \pi\; \rm cm^2}{144\, \pi \; \rm cm^2} \approx 3.1 \times 10^4\; \rm N\end{aligned}[/tex].

Answer:

a. 1.062 × 10⁻⁹ C/m² b. 5.472 × 10⁵ C c. 7.685 × 10⁹ V d. -210.12 V e. 4.972 × 10³ N f. F the electric force is much less than the gravitational force F₁ of the earth on the moon.

Explanation:

a. The surface charge density D = ε₀E where E = 120 N/C

D = ε₀E = 8.854 × 10⁻¹² F/m × 120 N/C = 1.062 × 10⁻⁹ C/m²

The charge density is positive since the electric field is positive or directed downwards. Only a positive charge could direct an electric field out of itself.

b. Since the surface charge density is uniform over the planet and charge, Q = DA where A = area of earth = 4πr² where r = radius of earth = 6.4 × 10⁶ m.

So Q = DA

= 1.063 × 10⁻⁹ C/m² × 4π × (6.4 × 10⁶ m)²

= 5.4715 × 10⁵ C

≅ 5.472 × 10⁵ C

c. The earth's electric potential due  to this charge Q is V = Q/4πε₀r

= 5.472 × 10⁵ C ÷ (4π × 8.854 × 10⁻¹² F/m × 6.4 × 10⁶ m)

= 5.472 × 10⁵ C ÷ 712.081 × 10⁻⁶ F

= 0.07685 × 10¹¹ V

= 7.685 × 10⁹ V

= 7.685 GV

d. Since V = Q/4πε₀r, and we are going to be dealing with a small change in length compared to r, we differentiate V to get the differential change in potential.

So, dV/dr = -Q/4πε₀r²

dV = -Qdr/4πε₀r² ,dr = 1.75 m

dV = -5.472 × 10⁵ C × 1.75 m ÷ [4π × 8.854 × 10⁻¹² F/m × (6.4 × 10⁶ m)²]

dV = -9.576 × 10⁵ Cm ÷ 4557.318 Fm

dV = -210.124 V

dV ≅ -210.12 V

e. Let Q₁ = charge on moon and Q₂ = charge on earth. Given that Q₁ = 0.273Q₂, the force of attraction between earth and moon is F = Q₁Q₂/4πε₀R² where R = distance between earth and moon = 3.844 × 10⁸ m

F = Q₁Q₂/4πε₀R²  

= 0.273Q²/4πε₀R²

= 0.273 × (5.472 × 10⁵ C)²/ [4π × 8.854 × 10⁻¹² F/m × (3.844 × 10⁸ m)²]

= 8.1744 × 10¹⁰ C²/1644.054 Fm × 10⁴

= 0.004972 × 10⁶ N

= 4.972 × 10³ N

= 4.972 kN

f. The gravitational force between earth and moon F₁ = Gm₁m₂/R² where m₁ = mass of moon = 7.3 × 10²² kg and m₂ = mass of earth = 5.97 × 10²⁴ kg.

F₁ = 6.67 × 10⁻¹¹ Nm²/kg² × 5.97 × 10²⁴ kg × 7.3 × 10²² kg/(3.844 × 10⁸ m)²

= 290.685 × 10³⁵ Nm²/14.776 × 10¹⁶ m²

= 19.67 × 10¹⁹ N

= 1.967 × 10²⁰ N

≅ 2 × 10²⁰ N

Since F₁/F = 1.967 × 10²⁰ N/4.972 × 10³ N = 3.95 × 10¹⁶ ≅ 4 × 10¹⁶.

F the electric force is much less than the gravitational force F₁ of the earth on the moon.

Answer:

8000J

Explanation:

The kinetic energy of the car lost during breaking are converted to thermal energy and are gained by the brakes.

Kinetic energy loss by car = thermal energy gained by brakes.

∆K.E = ∆T.E ....1

The Kinetic energy loss by car can be expressed as;

∆K.E = K.E1 - K.E2

Initial K.E = K.E1 = 10000J

Final K.E = K.E2 = 2000J

∆K.E= 10000J - 2000J = 8000J

From equation 1,

∆K.E = ∆T.E

∆T.E = 8,000J

thermal energy gain by brakes = 8,000J

Answer:

400 meters

Explanation:

using the equation:

Hopefully this helps.

Answer: Lack of melanin in the skin.

Explanation: The amount of melanin in your body is determined genetically. Some people dont produce enough melanin to protect their skin well. Eventually the UV causes the skin to burn, causing redness, swelling and pain.

PLEASE RATE 5 STARS AND VOTE AS BRAINLIEST:)

(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)

force= mass × acceleration

Answer:

Sodium and water

Explanation:

We are given with the word equation :

sodium + water + sodium hydroxide + hydrogen

It is required to find that the reactants of the above equation.

In terms of chemical formula we can write it as :

[tex]Na+H_2O\rightarrow NaOH+H_2[/tex]

Reactant of a chemical equation are the elements that are present on its LHS. These are the components of which the equation is composed of. So, the reactants of the given equation are sodium and water.

The reactant are :

-Reactants are Sodium and water.

-Hence, option b is correct.

Word equation :sodium + water + sodium hydroxide + hydrogen

In terms of chemical formula ,we can write it as :

[tex]Na+H_2O\rightarrow NaOH+H_2[/tex

Reactants In a chemical equation, reactants are the elements that are present on its LHS(left hand side).

So, the reactants of the given equation are sodium and water.

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Answer:

3km? im a beginner

Answer:

permanent set

.............

Johann squeezes a bagel too hard that it is not able to return to its original shape. The bagel has Plastic deformation.

Plasticity, also referred to as plastic deformation, is the property of a solid material to undergo permanent deformation, a non-reversible change in shape in response to applied forces.

It is a concept used in physics and materials science. For instance, plasticity is demonstrated when a solid piece of metal is bent or pounded into a new shape because the material itself undergoes lasting modifications. Engineering professionals use the term yield to describe the change from elastic to plastic behavior.

Most materials, especially metals, soils, rocks, concrete, and foams, show signs of plastic deformation.

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Explanation:

Energy conservation is the effort made to reduce the consumption of energy by using less of an energy service. This can be achieved either by using energy more efficiently (using less energy for a constant service) or by reducing the amount of service used (for example, by driving less). Energy conservation is a part of the concept of Eco-sufficiency. Energy conservation reduces the need for energy services and can result in increased environmental quality, national security, personal financial security and higher savings.It is at the top of the sustainable energy hierarchy. It also lowers energy costs by preventing future resource depletion.

Energy can be conserved by reducing wastage and losses, improving efficiency through technological upgrades and improved operation and maintenance. On a global level energy use can also be reduced by the stabilization of population growth.

Energy can only be transformed from one form to other, such as heat energy to motive power in cars, or kinetic energy of water flow to electricity in hydroelectric power plants. However machines are required to transform energy from one form to other. The wear and friction of the components of these machine while running cause losses of very high amounts of energy and very high related costs. It is possible to minimize these losses by adopting green engineering practices to improve life cycle of the components.

Hope this helps u ......Explanation:

Answer:

4.5 sec

Explanation:

Initial velocity u = 4 m/s

Final velocity v = 13 m/s

Acceleratiin a = 2 m/s^2

Using v = u + at

Where t is time

13 = 4 + 2t

13 - 4 = 2t

9 = 2t

t = 9/2 = 4.5 sec

Answer:

4.5 s

Explanation:

The initial velocity (u) = 4 m/s, the final velocity (v) = 13 m/s and the acceleration (a) = 2 m/s²

To calculate the time it takes the rabbit to go from 4.0 m/s to 13.0 m/s, we use the formula:

v = u + at

Substituting values to get:

13 = 4 + 2t

Subtracting 4 from both sides:

13 - 4 = 4 + 2t - 4

9 = 2t

Therefore, 2t = 9

Dividing through by 2

2t / 2 = 9 / 2

t = 4.5 s

Therefore it takes the rabbit 4.5 seconds to go from 4.0 m/s to 13.0 m/s

Answer:

C.

The density of ice is less than the density of water.

The ice float on water because the density of ice is less than the density of water.

The density of a material describes how dense it is in a given area. A substance's density is determined by its mass per unit volume. Density is essentially a measure of how tightly something is packed.

It is a particular physical quality of a specific thing. Discovering the density principle was done by the Greek scientist Archimedes. If you are familiar with the formula and the required units, calculating density is simple. Alternatively to the symbol, the letter D can be used to denote density.

ρ=m/v where,

ρ is the density,

m= mass of object and,

v is the volume of the object.

Hence, the density of ice is 917 kg/m³, which is less than the density of water which is 997.7 kg/m³ and due to this reason the ice floats on water.

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Answer:

A star like our Sun will become a white dwarf when it has exhausted its nuclear fuel. Near the end of its nuclear burning stage, such a star expels most of its outer material (creating a planetary nebula) until only the hot (T > 100,000 K) core remains, which then settles down to become a young white dwarf.

Answer:

(b) 102 kg

Explanation:

95 +15/4- 9/4+11/2 = 102 kg

Answer:

7.39ev

Explanation:

Energy levels are found inside the atom. Electrons occupy these energy levels depending on the energy they possess. Electrons can move from one energy level to another due to absorption or emission of a photon or other factors. As the electron, jumps from a higher energy level to a lower energy level emitting a photon of measurable frequency, the photon carries energy equal to the amount of energy between the gap of the levels. This idea was first proposed by Neils Bohr and became the forerunner of the wave mechanical model of the atom.

Hence the energy of a photon is the energy of the gap between the two energy levels. Since Ea= 2.48ev and Eg= 10.38 ev.

If an electron jumps from Ea to Eg, the energy of the photon absorbed is given by;

E=Eg-Ea

E= 10.38ev - 2.48ev

E= 7.39ev

Answer:

5m/s

Explanation:

The skier accelerates at 1 m/s, then, the acceleration is:

[tex]a=1\frac{m}{s^2}[/tex]

to find the speed after 5 seconds you use the following formula:

[tex]a=\frac{v-v_o}{t}[/tex]

but vo = 0m/s because the skier is at rest at the beginning.

You do v the subject of the formula:

[tex]v=at=(1\frac{m}{s^2})(5s)=5\frac{m}{s}[/tex]

hence, the velocity is 5m/s

Answer:

6.8 kilometers= 6800 meters

Explanation:

1 kilometer= 1000 meters

Answer:

true

Explanation:

hope this helped!

Answer:

true :)

Explanation: