John walked a distance of 900 meters in 10 minutes what was his average speed in kilomerters per hour

Answer:

Frequencia = 1.25 Hz

Explanation:

Dados los siguientes datos;

Para encontrar la frecuencia de la onda;

Matemáticamente, la velocidad de una onda viene dada por la fórmula;

[tex] Velocidad = Longitud \; de \; onda * Frequencia [/tex]

Haciendo de la frecuencia el tema de la fórmula, tenemos;

[tex] Frequencia = \frac {Velocidad}{Longitud \; de \; onda} [/tex]

Sustituyendo en la fórmula, tenemos;

[tex] Frequencia = \frac {50}{40} [/tex]

Frequencia = 1.25 Hz

Answer:

D

Explanation:

Cá xương, chim, thú, cá sấu không có sự pha trộn máu giàu O2 và máu giàu CO2 ở tim vì tim cá có 2 ngăn, tim các loài chim, thú, cá sấu có 4 ngăn

Answer:

The tendency of undisturbed objects to stay at rest or to keep moving with the same velocity is called inertia. This is why, the first law of motion is also known as the law of inertia.

Example.: A ball at rest on the ground continues to be at rest unless someone kicks it or any external force acts on it.

Explanation:

I hope this will help you buddy

Answer:

[tex]85\; \rm N[/tex].

Explanation:

The box is sliding with a constant speed in a fixed direction (to the right.) In other words the velocity of this box is constant. Hence, this box would be in a translational equilibrium. The acceleration of this box would be zero.

By Newton's Second Law of motion, the net force on this box would be [tex]0[/tex]. In other words, forces on this box are balanced.

The question is asking for the size of the friction on the box. Assuming that the floor is horizontal. The friction on this box would also be horizontal,

The only other force that could balance that friction would be the [tex]85\; \rm N[/tex] push to the right. The direction of this push is horizontal (to the right.) Hence, the entirety of that [tex]85\; \rm N\![/tex] would be in the horizontal direction.

Thus, forces on this box in the horizontal direction would be:

Since these two forces must balance each other, the size of the friction would also be [tex]85\; \rm N[/tex].

you need the number of seconds to calculate the distance. I'm assuming that the seconds were written in the question but you forgot to write the here, you can calculate the distance then and find the exact point where the cyclist stopped since you have the circumference. then you can find the angle (after finding the distance he cycled) by subtracting it from 360 since the circular path will have an angle of 360 degrees.

Although your question lacks some data A general answer is provided :

The angle made vertically  = 360° - x°

where x = angle at which the the cyclist stopped

and circumference of the circular path = Total Distance travelled by the cyclist

First step : determine the distance travelled by the cyclist vertically

circumference = 2*π*r

343 = 2*π * r

∴ r = 343 / ( 2π ) = 54.59

therefore distance travelled by the cyclist vertically = 54.59 * 2 = 109.18 m

Given that the time travelled is missing

assuming the angle to the distance travelled by the cyclist before it stopped vertically = 360° - x°  

This is because the Total angle of a circular path = 360°

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a) gia tốc = vf-vi / t

a = 14-10 / 20

a = 0,2ms⁻²

b) dưới dạng a = Δv / t

v = lúc

v = 0,2 × 40

v = 8ms⁻¹

như v = d / t

do đó d = vt

d = 8 × 40

d = 320m

hãy đánh dấu là trí óc nhất

Answer: i)A to B : (ice) freezing

ii) B to C (water) boiling

C to D  (steam) evaporating

explanation:  0° is the freezing point of water  when temperature increases from 0° the water starts melting. As 100° is the boiling point of water so at 100° the water  completely melts and it starts boiling during boiling water changes into steam(water vapour) and it evaporates

Answer:

The force is proportional to the area, for if we increase the area but keep the number of molecules per cubic centimeter the same, we increase the number of collisions with the piston in the same proportion as the area was increased.

Explanation:

more area =more space = more free for molecules = less pressure = less force.

Answer:

It's a pretty simple suvat linear projectile motion question, using the following equation and plugging in your values it's a pretty trivial calculation.

V^2=U^2+2*a*x

V=0 (as it is at max height)

U=30ms^-1 (initial speed)

a=-g /-9.8ms^-2 (as it is moving against gravity)

x is the variable you want to calculate (height)

0=30^2+2*(-9.8)*x

x=-30^2/2*-9.8

x=45.92m

Answer:

35

Explanation:

dfddffffffffffffdddfr

Explanation:

The wheel and axle is a type of simple machine used to make tasks easier in terms of manipulating force by applying the concept of mechanical advantage.

Explanation:

Newton's first law states that if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force.

Example a ball at rest remains at rest unless a net force is act on it. If u kick that ball, net force will act on it

This is why we called motion of inertia

[tex]\boxed{\sf Velocity=\dfrac{Displacement}{Time}}[/tex]

[tex]\\ \sf\longmapsto Velocity=\dfrac{1200}{240}[/tex]

[tex]\\ \sf\longmapsto Velocity=5m/s[/tex]

ripples on the surface of water.

vibrations in a guitar string.

a Mexican wave in a sports stadium.

electromagnetic waves – eg light waves, microwaves, radio waves.

seismic S-waves.

Answer

Light and other types of electromagnetic radiation are examples of transverse waves. Some other examples of transverse waves include a ripple on a pond and a wave in a string.

Answer:

a) The velocity of the object as a function of time, v(t) is 2·b·t

b) The acceleration of the function of time, a(t) is 2·b

c) The time at which the object is at the flagpole is t = √(c/b)

Explanation:

The function that gives the position of the object north of the flagpole, x(t) is presented as follows;

x(t) = b·t² - c (b and c are constants)

a) The velocity of the object as a function of time, v(t), is derived as follows

v(t) = x'(t) = d(b·t² - c)/dt = 2·b·t

The velocity of the object as a function of time, v(t) = 2·b·t

b) The acceleration of the function of time, a(t) = v'(t) = d(2·b·t)/dt = 2·b

c) The time at which the object is at the flagpole is given by the x-intercept of the function, where x(t) = 0, as follows;

At the x-intercept, we have, x(t) = 0 and x(t) = b·t² - c

∴ 0 = b·t² - c, which gives

b·t² = c

t² = c/b

t = ±√(c/b), we reject the negative value to get;

The time at which the object is at the flagpole, t = √(c/b).

Answer:

Alkali metals

Explanation:

Elements in this group are highly reactive, soft, lustrous and highly conductive.

An element which is highly conductive, highly reactive, soft, and lustrous is most likely an alkali metal.

Alkali metals are in group 1 of the Periodic table which means that they have only a single valence electron.

This causes them to be soft and highly reactive because:

Examples of alkali electrons include:

In conclusion therefore, alkali metals are highly reactive and soft and so the element described above is most likely an alkali metal.

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Answer:

force=mass×acceleration

hence

acceleration is given by force÷mass

(500÷200)*5=12.5

Answer:

I. Period = 1.3 seconds

II. Frequency = 0.769 Hertz

Explanation:

Given the following data;

Number of oscillation = 240 cycles

Time = 5.2 minutes.

Conversion:

1 minute = 60 seconds

5.2 minutes = X seconds

X = 60 * 5.2

X = 312 seconds

To find the following;

I. Period

Mathematically, the number of oscillation of a pendulum is given by the formula;

[tex] Number \; of \; oscillation = \frac {Time}{Period} [/tex]

Making period the subject of formula, we have;

[tex] Period = \frac {Time}{Number \; of \; oscillation} [/tex]

Substituting into the formula, we have;

[tex] Period = \frac {312}{240} [/tex]

Period = 1.3 seconds

II. Frequency

[tex] Frequency = \frac {1}{Period} [/tex]

Substituting the values into the formula, we have;

[tex] Frequency = \frac {1}{1.3} [/tex]

Frequency = 0.769 Hertz

Answer:

8392

Explanation:

d=s/t

Answer:

a) v = 0.4799 m / s,  b)  K₀ = 1600.92 J,    K_f = 5.46 J

Explanation:

a) How the two players collide this is a momentum conservation exercise. Let's define a system formed by the two players, so that the forces during the collision are internal and also the system is isolated, so the moment is conserved.

Initial instant. Before the crash

        p₀ = m v₁ + M v₂

where m = 95 kg and his velocity is v₁ = -3.75 m / s, the other player's data is M = 111 kg with velocity v₂ = 4.10 m / s, we have selected the direction of this player as positive

Final moment. After the crash

       p_f = (m + M) v

as the system is isolated, the moment is preserved

       p₀ = p_f

       m v₁ + M v₂ = (m + M) v

       v =[tex]\frac{m v_1 + M v_2}{m+M}[/tex]

let's calculate

        v = [tex]\frac{ -95 \ 3.75 \ + 111 \ 4.10}{95+111}[/tex]

        v = 0.4799 m / s

b) let's find the initial kinetic energy of the system

         K₀ = ½ m v1 ^ 2 + ½ M v2 ^ 2

         K₀ = ½ 95 3.75 ^ 2 + ½ 111 4.10 ^ 2

         K₀ = 1600.92 J

the final kinetic energy

         K_f = ½ (m + M) v ^ 2

         k_f = ½ (95 + 111) 0.4799 ^ 2

         K_f = 5.46 J

Answer:

  an object sliding down hill

Explanation:

On a slope, the force applied is due to gravity. Its direction is straight down. If the object is sliding down the hill, its displacement is at an angle to the applied force. The angle of displacement will depend on the steepness of the hill.

Answer:

Scattering of light is the phenomenon in which light rays get deviated from its straight path on striking an obstacle like dust or gas molecules, water vapours etc. Scattering of light gives rise to many spectacular phenomena such as Tyndall effect and the “red hues of sunrise and sunset”.

Answer:

The wavelength of the photon that would have the same momentum as the electron is 202.2180996 nm

Explanation:

The velocity of the electron, v = 3.6 × 10³ m/s

The momentum of an electron, [tex]p_e[/tex] = m × v

Where;

v = The mass of the electron = 9.109 × 10⁻³¹ kg

∴ [tex]p_e[/tex] = 9.109 × 10⁻³¹ kg × 3.6 × 10³ m/s = 3.27924 × 10⁻²⁷ kg·m/s

According to the de Broglie equation, the momentum of a photon, p, is given as follows;

p = h/λ

Where;

h = 6.63 × 10⁻³⁴ J·s

λ = The wavelength of the photon

∴ λ = h/p

According to the question, we have;

p = [tex]p_e[/tex] = 3.27924 × 10⁻²⁷ kg·m/s

∴ λ = 6.63 × 10⁻³⁴ J·s/(3.27924 × 10⁻²⁷ kg·m/s) = 2.02180993 × 10⁻⁷ m

The wavelength of the photon, λ = 2.02180993 × 10⁻⁷ m = 202.2180993 × 10⁻⁹ m = 202.2180993 nm.

Answer:

Velocity ratio = distance travelled by effort / distance travelled by load. Which is equal to effort arm / load arm. When velocity ratio (VR) is 4, the effort arm is greater than load arm.

Answer:

an element with a small number of valence electrons and a large atomic radius

Answer:

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.

Explanation:

Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors as discrete components can be composed of various compounds and forms. Resistors are also implemented within integrated circuits.

The electrical function of a resistor is specified by its resistance: common commercial resistors are manufactured over a range of more than nine orders of magnitude. The nominal value of the resistance falls within the manufacturing tolerance, indicated on the component.

The Weight of an object is more at pole and less at equator of the earth because the distance of the pole is less than the distance of the equator from the centre of the earth.