Please help me understand this

Answer:

If the athlete speeds up between 2 points there is an increase of the athlete's "kinetic" energy

I guess this would imply a decrease in the athlete's chemical energy because the energy has to originate somewhere

Answer:

4950 watt hours.

Explanation:

450*1 + 3000*1.5 = 4950w

Answer:

D

Explanation:

Work is not a vector but it is a scalar

Answer:

D

Explanation:

D. its is a vector which is always in the same direction as the displacement

The net force acting on the car is equal to -12000 Newton.

Given the following data:

To determine the net force acting on the car:

Mathematically, the net force acting on the car is given by Newton's Second Law of Motion:

[tex]F = \frac{m(v\;-\;u)}{t}[/tex]

Where:

Substituting the given parameters into the formula, we have;

[tex]F = \frac{1200 \times (0\;-\;30)}{3}\\\\F = \frac{1200 \times (-30)}{3}\\\\F = \frac{-36000 }{3}[/tex]

Net force = -12000 Newton.

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Answer:

Answer:

H = 1/2 g t^2     time to reach top of trajectory

v = g t   time to reach top of trajectory when v is initial speed upwards

v = 5 g = 49 m/s      5 sec upwards and 5 sec downwards

Answer:

1/9

Explanation:

9/27 3 can go in both way

Answer:

D

Explanation:

The best description of a p-type semiconductor is It uses boron so that electrical conduction is due to the movement of a positive charge.THe correct option is D.

A p-type semiconductor is created by doping a pure semiconductor material, such as silicon, with an impurity that has one less electron than the semiconductor. Boron, which has three valence electrons, is commonly used as a dopant to create p-type semiconductors.

When boron atoms are introduced into a pure semiconductor material such as silicon, they create "holes" in the crystal lattice structure. These holes can be thought of as vacancies where an electron would normally be. The holes are positively charged and can move around the crystal lattice structure. When an electric field is applied to the p-type semiconductor, the holes move towards the negative electrode, and this movement of holes is what causes electrical conduction in a p-type semiconductor.

Therefore, the statement that best describes an example of a p-type semiconductor is "It uses boron so that electrical conduction is due to the movement of a positive charge."

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Answer: The name of the unit is A.U's(Astronomical unit)

Explanation:

Answer:State the question so I can answer

Explanation:

Answer:

The reason X-rays are used in this process is because the clouds of electrons are at the same scale as the X-ray radiation wavelength. This means that the radiation is deflected and scattered by the electrons of the atoms in the crystal. The deflected X-ray beams produce a scattering distribution which is proportional to the scattering angle.

Explanation:

Answer:

Because X-rays have wavelengths similar to the size of atoms, they are useful to explore within crystals. Thus, since X-rays have a smaller wavelength than visible light, they have higher energy. With their higher energy, X-rays can penetrate matter more easily than can visible light.

Explanation:

The block's potential energy at the top of the incline (at a height h from the horizontal surface) is equal to its kinetic energy at the bottom of the incline, so that

mgh = 1/2 mv²

where v is its speed at the bottom of the incline. It follows that

v = √(2gh)

If the incline is 20.4 m long, that means the block has a starting height of

sin(15°) = h/(20.4 m)   ⇒   h = (20.4 m) sin(15°) ≈ 5.2799 m

and so the block attains a speed of

v = √(2gh) ≈ 10.1728 m/s

The block then slides to a rest over a distance d. Kinetic friction exerts a magnitude F over this distance and performs an amount of work equal to Fd. By the work-energy theorem, this quantity is equal to the block's change in kinetic energy, so that

Fd = 0 - 1/2 mv²   ⇒   d = (-1293.58 J)/F

By Newton's second law, the net vertical force on the block as it slides is

∑ F [vertical] = n - mg = 0

where n is the magnitude of the normal force, so that

n = mg = (25 kg) g = 245 N

and thus the magnitude of friction is

F = -0.16 (245 N) = -39.2 N

(negative since it opposes the block's motion)

Then the block slides a distance of

d = (-1293.58 J) / (-39.2 N) ≈ 32.9994 m ≈ 33 m

The mass of the sour cream that should be added is 0.68 kg.

Mass of the water is calculated as follows;

mass = density x volume

mass = (1 kg/L) x 0.5 L = 0.5 kg

Heat gained by the sour cream = Heat lost by the water

[tex]m_s c_s\Delta \theta _s = m_wc_w\Delta \theta _w\\\\m_s = \frac{m_wc_w\Delta \theta _w}{c_s\Delta \theta _s} \\\\[/tex]

where;

[tex]m_s = \frac{0.5 \times 4184 \times (80 - 40)}{3510 \times (40 - 5)} \\\\m_s = 0.68 \ kg[/tex]

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Half maximum velocity occurs at the point of half maximum kinetic energy which is exactly halfway down.

The principle of conservation of energy states that energy can neither be created nor destroyed but can be converted from one form to another.

M.A = K.E + P.E

At the maximum height, the kinetic energy of the ball while potential energy is maximum.

At the half-way down, the ball kinetic energy of the ball is equal to the potential energy.

Thus, half maximum velocity occurs at the point of half maximum kinetic energy which is exactly halfway down.

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is it a multi or is it writing

Answer:

2/3V

Explanation:

Given that a ball of mass M and speed V collides with another ball of mass 2M and velocity v/2 . After collision they stick together and we need to find their speed after collision . According to Law of Conservation of Momentum , The total momentum of the system before and after collision is constant .That is ;

[tex]\sf\qquad\longrightarrow m_1u_1+m_2u_2=m_1v_1+m_2v_2\\ [/tex]

[tex]\sf\qquad\longrightarrow MV + 2M\bigg(\dfrac{V}{2}\bigg) = (2M + M)(v)\\ [/tex]

[tex]\sf\qquad\longrightarrow MV +MV= 3Mv\\[/tex]

[tex]\sf\qquad\longrightarrow 2MV = 3Mv\\ [/tex]

[tex]\sf\qquad\longrightarrow v =\dfrac{2M}{3M}V\\ [/tex]

[tex]\sf\qquad\longrightarrow \pink{ v_{after\ collision}=\dfrac{2}{3}V }[/tex]

Hence the velocity after the collision ia 2/3V .

The products have different arrangement of atoms to the reactants.

Products are substances which are produced from the chemical changes that occur in the substances.

Reactants are the substances which form products as a result of  chemical changes that occur in them.

The reactants and products in a chemical reaction contain the same atoms, but the arrangement of their atoms differs.

Therefore, the products have different arrangement of atoms to the reactants.

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The direction of the net force is up.

The net force on the charges can be determined using Coulomb's law as follows;

[tex]F_{AC} = + \frac{KQ^2}{r^2}[/tex]

[tex]F_{BC} = - \frac{KQ^2}{r^2}[/tex]

F(net) = F(AC) + F(BC)

F(net) = 0

The, direction of the net force on charge C will be parallel to charge C to achieve a zero net force. Thus, the direction of the net force is up.

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Answer:

155/62 = 2.5

Mass/Volume = Density

Density= 2.5

Explanation:

[tex] \huge \frac{1}{v} + \frac{1}{u} = \frac{1}{f}[/tex]

where,

v:distance of the image from the lens

u:distance of the object from the lens;

f:focal length,

Explanation:

Distance : 600 m

Time : 33 seconds

Average Speed : ?

[tex]Av. Speed = \frac{Distance }{Time} \\ = \frac{600}{33} [/tex]

Simplify

[tex]Av. Speed = 18.18181 \\ = 18 \: m {s}^{ - 1} [/tex]

1.) c

2.) d

3.) d

4.) b

5.) c

We will find the acceleration using the formula of force. The formula states that the net force applied on an object is directly proportional to the product of mass of the body and the acceleration of the body...

[tex] \mathcal{F = MA}[/tex]

Where,

In our case,

[tex]\large\underline{\underline{\maltese{\orange{\pmb{\sf{\: Solution :-}}}}}}[/tex]

➪ Therefore, The acceleration of the body is 7.7 m/s²...~

According to the given statement The acceleration of the body is 7.7 m/s².

Acceleration refers to the rate at which speed and direction of velocity vary over time. A point or object moving straight ahead is pushed when it accelerates or decelerates. Even though the speed is constant, movement on a circle accelerates so because direction is constantly shifting.

F is force = 270N

M is mass = 35 kg

A is acceleration = unknown

F = m* a

270 = 35 * a

270 = 35a

35a = 270

a = 270/35

a = 7.7 m/s².

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Answer:

The electrolysis of zinc chloride shows how an ionic salt will conduct electricity when molten, but not when solid.

Explanation:

hope this helps!!!! GOOD LUCK!!!!

Raising the hook, or load by exactly 1 meter, will allow the length of the compressed material regain its original length, provided it wasn't deformed by the 5% compression.

Hooke's law states that the force applied to an elastic material is directly proportional to the extension of the material provided that the elastic limit of the material is not exceeded.

When the length of the material is compressed by 5%, the material will regain its original size and shape when the applied load is removed, if the material was not deformed by the compression.

Thus, raising the hook, or load by exactly 1 meter, will allow the length of the compressed material regain its original length, provided it wasn't deformed by the 5% compression.

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