why the shape of the earth is spherical

Answer:

When an object falls, its gravitational potential energy is changed to kinetic energy. ... Gravitational potential energy for a mass m at height h near the surface of the Earth is mgh more than the potential energy would be at height 0. (It's up to you where you choose height 0.)

Explanation:

Answer:

Qwertyujiknb vcdxrftyhbvcdxrft6y7uij

Explanation:

Answer:

B.The box experiences less friction on the marble floor

Explanation:

Answer:

B. The Box experiences less friction on the marble floor

Explanation:

This is because the the carpet is not a flat surface and the marble is smooth

Acceleration = (change in speed) / (time for the change)

Change in speed = (speed after the change) - (speed before the change)

Change in speed = (65 m/s) - (35 m/s)  =  30 m/s

Acceleration = (30 m/s) / (5 s)

Acceleration = 6 m/s²

Answer:

Explanation:

The quantity of heat required to raise the temperature of water to 100 degrees is expressed as

[tex]Q= mc(T2-T1)[/tex]

Given data

mass of water = 5kg

initial temperature T1= 20 °C

final temperature T2= 100 °C

Specific heat capacity of water=  4 200 J/Kg °C

[tex]Q= 5* 4 200(100-20)\\Q= 21000(80)\\Q= 1680000\\Q= 1680kJ[/tex]

Answer:

Final velocity (v) = 36 m/s

Distance traveled (s) = 2,160 m

Explanation:

Given:

Initial velocity (u) = 0

Acceleration (a) = 0.3 m/s

Time travel (t) = 2 minutes = 120 seconds

Find:

Final velocity (v) = ?

Distance traveled (s) = ?

Computation:

v = u + at

v = 0 + 0.3(120)

v = 0.3(120)

v = 36 m/s

Final velocity (v) = 36 m/s

Distance traveled (s) = ut + (1/2)at²

Distance traveled (s) = (0.5)(0.3 × 120 × 120)

Distance traveled (s) = 2,160 m

Answer:

I think it is better if you read and shortly write my explanation

Explanation:

simple pendulum with no friction, mechanical energy is conserved. Total mechanical energy is a combination of kinetic energy and gravitational potential energy. As the pendulum swings back and forth, there is a constant exchange between kinetic energy and gravitational potential energy.

Answer: - 452.088joule

Explanation:

Given the following :

Mass of water = 12g

Change in temperature(Dt) = (11 - 20)°C = - 9°C

Specific heats capacity of water(c) = 4.186j/g°C

Q = mcDt

Where Q = quantity of heat

Q = 12g × 4.186j/g°C × - 9°C

Q = - 452.088joule

Answer:

2.331

Explanation:

It just the change of Energy from potential (PE) to kinetic (KE)

PE on A = PE on B + KE on B + friction works (Wf)

mg(ha) = mg(hb) + ½mv² + Wf

35 * 9.8 * 1.5 = 35 * 9.8 * 0.8 + ½ * 35 * v² + 145

514.5 = 274.4 + 17.5v² + 145

514.5 - 274.4 - 145 = 17.5v²

17v² = 95.1

v² = 5.434

v =√5.434 = 2.331 m/s

Answer:

Infinity = Never ending

Explanation:

The universe could be infinite, both in terms of space and time, but there is currently no way to test whether it goes on forever or is just very big. The part of the universe we are able to observe is finite, measuring about 46 billion light years in diameter.

The set of natural numbers is an infinite set. This kind of infinity is, by definition, called countable infinity. All sets that can be put into a bijective relation to the natural numbers are said to have this kind of infinity. This is also expressed by saying that the cardinal number of the set is aleph-naught (ℵ0).

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STARS ARE INFINITE , NUMBERS ARE INFINITE

Explanation:

Answer: - 7500N

Explanation:

Given the following :

Initial Velocity of car = 108km/hr

Time taken to stop after applying brakes = 4s

Mass of passengers in car = 1000kg

Force exerted by the brakes on the car =?

After 4s, then final Velocity (V) = 0

Initial Velocity (u) of the car = 108km/hr

108km/hr = (108 × 1000)m ÷ (3600)s = 30m/s

Force exerted = mass(m) × acceleration(a)

Acceleration of car = Change in Velocity with time

a = (v - u) / t

a = (0 - 30) / 4

a = - 30/ 4

a = - 7.5m/s^2

Therefore,

Force exerted = mass(m) × acceleration(a)

Force exerted = 1000kg × (-7.5)m/s^2

Force exerted = - 7500N

Answer:

The force exerted by the brakes on the motor car is -7500 N.

Explanation:

Given :-

To find :-

Solution :-

Since the car stops, the final velocity (v) will be 0 m/s.

• Initial velocity (u) = 108 km/h.

Converting initial velocity into m/s.

We know that,[tex] \sf{1\:km/h=\dfrac{5}{18}\:m/s}[/tex]

Then initial velocity,

= [108 × 5/18 ] m/s

= 30 m/s

Now find the force exerted by the brakes.

★ Formula used :

[tex]{\boxed{\sf{F=\dfrac{m(v-u)}{t}}}}[/tex]

[tex]:\implies \sf \: F= \dfrac{1000(0 - 30)}{ 4} \\ \\ : \implies \sf \: F \: = \dfrac{ - 30000}{4} \\ \\ : \implies \sf \: F \: = - 7500[/tex]

The force exerted by the brakes on the motor car = -7500 N.

•The negative sign of force(F) means that the force was applied in opposite direction of motion.

Explanation:

Veins carry deoxygenated blood from different parts of the body to our heart. ... Since a larger volume of blood is collected in the right auricle than that of the left auricle, right auricle is larger than the left auricle.

Answer:

NO.

Explanation:

METALLIC BOND IS ONLY IN METALS.

Since iron is a metal and carbon a non- metal, they cannot form a metallic bond.

Answer:

B

Explanation:

One positive charger and one negative charger

Answer:

There is no answer, since a closed-pipe resonator can NOT have a second harmonic. However, if you were to plug the pipe length and the speed of sound into the closed-pipe equation anyway you would get 49.56 as your fundamental frequency, which means that 99.13 would be your "plug and play" 2nd harmonic.

Explanation:

Answer:

A

Explanation:

Answer: A

Explanation:

Answer:

The hunter should aim directly at the perched monkey because the tranquilizer dart will fall away from the line sight at the same rate that the monkey falls from its perch.

Tan theta = 9 / 90 = .1      so theta = 5.71 deg

The time for the monkey to reach the ground is

t = (2 h / g)^1/2 = (18 / 9.8)^1/2 = 1.36 sec

So the horizontal speed of the dart must be at least

Vx = 90 m / 1.36 sec = 66.4 m/s

Vx = V cos theta

V = 66.4 m/s / cos 5.71 = 66.7 m/s

The angle of projection of the tranquilizer dart is 5.7⁰

The horizontal speed of the tranquilizer dart is 66.5 m/s

The given parameters;

The angle of projection of the tranquilizer dart is calculated as;

[tex]tan(\theta) = \frac{y}{x} \\\\tan(\theta) = \frac{9}{90} \\\\tan(\theta) = 0.1\\\\\theta = tan^{-1}(0.1)\\\\\theta = 5.71 ^0[/tex]

The speed of the tranquilizer dart is calculated as;

X = v₀ₓt

where;

t is the time to reach maximum height

X is the horizontal displacement = 90 m

The time to reach maximum height is calculated as;

[tex]h = v_0_yt + \frac{1}{2} gt^2\\\\h = 0 + \frac{1}{2} gt^2\\\\h = \frac{1}{2} gt^2\\\\t = \sqrt{\frac{2h}{g} } \\\\t = \sqrt{\frac{2\times 9}{9.8} } \\\\t = 1.36 \ s[/tex]

The horizontal speed of the tranquilizer dart is calculated as;

[tex]X = v_0cos(\theta) \times t\\\\90 = v_0\times cos(5.71) \times 1.36\\\\90 = 1.353 v_0\\\\v_0= \frac{90}{1.353} \\\\v_0 = 66.5 \ m/s[/tex]

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Answer:

a) Shadow distance

10 cm in front of the mirror.

b) Zoom in the shadow

The shadow formed is the same height as the object and is placed also at the centre of curvature of the mirror as shown in the attached image to this solution.

c) The nature of the shadow

The shadow formed is real, inverted, same size as the object and formed at the centre of curvature.

Explanation:

English Translation

Objects as high as 3 cm are placed at a distance of 10 cm in front of a concave mirror with 10 cm curvature. Determine:

a) Shadow distance

b) Zoom in the shadow

c) The nature of the shadow

Solution

The mirror equation is given as

(1/f) = (1/v) + (1/u)

f = focal length of the mirror = (radius of curvature)/2 = 10/2 = 5 cm

v = image distance = ?

u = object distance = 10 cm

We can then calculate the shadow' s distance from the mirror thus

(1/5) = (1/v) + (1/10)

(1/v) = 0.2 - 0.1 = 0.1

v = (1/0.1) = 10 cm

b) Zoom in the shadow

Since the object is placed at the centre of curvature, as shown in the attached image, the image is formed at a point of intersection of rays. The image formed is the same height as the object and is placed also at the centre of curvature of the mirror.

c) The nature of the shadow

Since the mirror is a concave mirror, the image is real and formed in front of the mirror. The image is also inverted and formed at the centre of curvature of the mirror.

Hope this Helps!!!

Answer:

The wavelength of the wave is 2.34 nm.

Explanation:

It is required to find the wavelength of a [tex]1.28\times 10^{17}\ Hz[/tex] wave. A wave moves with a speed of light. Speed of a wave is given in terms of wavelength and frequency. So,

[tex]v=f\lambda[/tex]

[tex]\lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{3\times 10^8}{1.28\times 10^{17}}\\\\\lambda=2.34\times 10^{-9}\ m\\\\\text{or}\\\\\lambda=2.34\ nm[/tex]

So, the wavelength of the wave is 2.34 nm.

The wavelength of the wave is 2.34 × 10⁻⁹ meters.

Given the data in the question;

Wavelength; [tex]\lambda =\ ?[/tex]

To determine the wavelength of the wave, we use the expression for the relations between wavelength, frequency and speed of light.

[tex]\lambda = \frac{c}{f}[/tex]

Where [tex]\lambda[/tex] is wavelength, f is frequency and c is speed of light ( [tex]3*10^8m/s[/tex] )

We substitute our values into the equation

[tex]\lambda = \frac{3*10^8m/s}{1.28*10^{17}Hz} \\\\\lambda = \frac{3*10^8m/s}{1.28*10^{17}s^{-1}} \\\\\lambda = 2.34 * 10^{-9}m[/tex]

Therefore, the wavelength of the wave is 2.34 × 10⁻⁹ meters.

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'''In a series circuit, the sum of the voltages consumed by each individual resistance is equal to the source voltage. Components connected in parallel are connected along multiple paths so that the current can split up; the same voltage is applied to each component.''

Answer:

Yes, in case of uniform velocity

Explanation:

This is the case of uniform velocity. If a body covers equal displacement in equal intervals of time, then the velocity of a body is said to be ‘Uniform Velocity’. It meas that the velocity of a body remains constant during the motion and it does not change.

Since, acceleration is defined as the rate of change of velocity.

Therefore, if there is no change in velocity or in other words the change in velocity is zero, then the acceleration is also zero.

a = ΔV/t = 0/t

a = 0 m/s²

So, the acceleration of the body is 0 m/s², but it has a uniform velocity

Hence, it is possible for an object that, object with zero acceleration have velocity, which is the case case of uniform velocity.

A cord is wrapped around the outer surface of the 8-kg disk. If a force of F = (1⁄4θ²) N, where θ is in radians, is applied to the cord, determine the disk’s angular acceleration when it has turned 5 revolutions. The disc has an initial angular velocity [tex]\omega _o = 1 \ rad/s[/tex] and radius from the center of the disc = 300 mm

Answer:

the angular acceleration = 205.706 rad/sec²

Explanation:

GIVEN THAT:

The disc mass = 8 kg

Force = [tex]\dfrac{1}{4} \ \ \theta ^2* N[/tex]

We are told that the given θ is in radians; Therefore; the when it has turned 5 revolutions; we have the θ to be:

[tex]\theta = 5 rev * (\dfrac{2 \ \pi * rad}{1 rev}) \\ \\ \theta = 10 \ \pi \ rad[/tex]

Also;

the initial angular velocity [tex]\omega _o = 1 \ rad/s[/tex]

radius from the center of the disc = 300 mm = 0.3 m

Thus; the mass moment about the Inertia can be determined via the following expression;

[tex]I_o = \dfrac{1}{2}*m*r^2[/tex]

[tex]I_o = \dfrac{1}{2}*8*0.3^2[/tex]

[tex]I_o = 0.36 \ kg/m^3[/tex]

Now to calculate the angular acceleration; we equate the sum of the moments acting on the Inertia;

SO:

[tex]\sum M_o = I_o \alpha[/tex]

[tex]F*0.3 = 0.36* \alpha[/tex]

[tex]\dfrac{1}{2}* \theta^2 *0.3 = 0.36* \alpha[/tex]

[tex]\alpha = 0.20836 \ \theta^2 \ rad/sec^2[/tex]

[tex]\alpha = 0.20836 \ (10 \ \pi )^2 \ rad/sec^2[/tex]

[tex]\alpha = 205.706 \ rad/sec^2[/tex]

Hence; the angular acceleration = 205.706 rad/sec²

Answer:

a_max = 50 cm/s^2

Explanation:

To find the magnitude of the maximum acceleration of the particle, you take into account the equation of motion in a simple harmonic motion:

[tex]x=Acos(\omega t)[/tex]

ω: angular velocity = 10 rad/s

A: amplitude = 5 cm

The acceleration is given by:

[tex]a=\omega^2 x[/tex]

and the maximum acceleration is obtained when the cosine function is maximum, that is, when cos(wt) = 1. Then, you have:

[tex]a_{max}=\omega^2 x_{max}=\omega^2A[/tex]

Then, you replace the values of w and A in order to calculate a_max:

[tex]a_{max}=(10rad/s)^2(5cm)=50\frac{cm}{s^2}[/tex]

hence, the maximum acceleration is 50 cm/s^2

Answer:

80 Percent

Explanation:

E=energy output/energy input×100

E=8000/10000×100

E=0.8×100

E=80 percent.

Mark brianliest if my answer suit your question

If the machine put, in 8000 J, and the user puts 10,000 J of work then the efficiency of the machine will be equal to 80%.

Work is a physics term used to describe the transfer of energy that takes place when an object changes above a distance because of an external force, at least some of which is given in the vector of the dislocation. The element of the force acting all along the path multiplied by the length of the path can be used to calculate work if the force is constant.

Mathematically, this idea is expressed as W = fd, where W is the effort and f is the force multiplied by d, the distance. Work is completed whenever the force is applied at an angle with about the displacement.

As per the data provided in the question,

Total input energy = 10,000 J

Total output energy = 8,000 J

Then, the efficiency (η) of the machine will be,

η = (output energy/input energy) × 100

η = 8000/10000 × 100

η = 80%.

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Explanation:

2) C would need the least effort, because the longer the effort distance, the least the effort applied.

Explanation:

R = [tex]\sqrt{(12.0)^{2} + (9.00)^{2}}[/tex] = 15 UNIDADES

The boat has to pull with MORE force. Don't forget about the force of friction with the water, pulling the skier in the backwards direction. The force that accelerates him is the NET force ... boat force minus water resistance. So the boat force has to be greater than the net accelerating force.

Answer:

-7500 N

Explanation:

v₀ = 108 km/h = 30 m/s

v = 0 m/s

t = 4 s

a = Δv / Δt

a = (0 m/s − 30 m/s) / 4 s

a = -7.5 m/s²

F = ma

F = (1000 kg) (-7.5 m/s²)

F = -7500 N

Answer:-7500

Explanation v₀ = 108 km/h = 30 m/s

v = 0 m/s

t = 4 s

a = Δv / Δt

a = (0 m/s − 30 m/s) / 4 s

a = -7.5 m/s²

F = ma

F = (1000 kg) (-7.5 m/s²)

F = -7500 N