Please help! Will mark brainliest!

Answer:

70200J

Explanation:

k.E = 1/2mv^2

K.E = 1/2(3900)(6)^2

Answer: The live wire is the most dangerous one, since it is at 230 V. it should never touch the earth wire (unless the insulation is between them, of course!), because this would make a complete circuit from your mains supply to the ground (earth). A shock or fire would be highly likely.

Explanation:

Answer:

B. Longitudinal wave

Explanation:

It's the only option that makes sense. Hope this helped :)

The lawnmower accelerates in the positive horizontal direction, so that the net horizontal force is, by Newton's second law,

(70 N) cos(-50°) = m (1.8 m/s²)

where m is the mass of the lawnmower. Solve for m :

m = ((70 N) cos(-50°)) / (1.8 m/s²)

m ≈ 25 kg

The lawnmower presumably doesn't get lifted off the ground, so that the net vertical force is 0. If n is the magnitude of the normal force, then by Newton's second law,

n - m g + (70 N) sin(-50°) = 0

n = m g + (70 N) sin(50°)

n = (25 kg) (9.8 m/s²) + (70 N) sin(50°)

n ≈ 300 N

Answer:

C. seismographs

Explanation:

Theirs another name for seismographs but c is correct

Answer:

Q = 364.25 kcal

Explanation:

In this question, we will have to calculate the heat absorptions for different steps of temperature rise and phase change. And then we will ad them to calculate total heat absorbed.

1. RISE IN TEMPERATURE OF ICE:

First, the temperature of ice will be increased from - 10°C to 0 °C. Heat absorbed during this process will be given as:

Q₁ = mC₁ΔT₁

where,

Q₁ = Heat absorbed while increasing temperature of ice = ?

m = mass of ice = 0.5 kg

C₁ = specific heat of ice = 0.5 kcal/kg k

ΔT₁ = change in temperature of ice = 0 - (-10) = 10 k

Therefore,

Q₁ = (0.5 kg)(0.5 kcal/kg.k)(10)

Q₁ = 2.5 kcal

2. MELTING OF ICE:

Now, the melting of ice will occur at 0°C and the heat absorbed during this process will be:

Q₂ = m(Latent Heat of Fusion of Ice)

where,

Q₂ = heat Absorbed during melting of ice = ?

Therefore,

Q₂ = (0.5 kg)(79.7 kcal/kg)

Q₂ = 39.85 kcal

3. RISE IN TEMPERATURE OF WATER:

Now, the temperature of water will be increased from 0°C to 100 °C. Heat absorbed during this process will be given as:

Q₃ = mC₃ΔT₃

where,

Q₃ = Heat absorbed while increasing temperature of water = ?

m = mass of water = 0.5 kg

C₃ = specific heat of water = 1 kcal/kg k

ΔT₃ = change in temperature of ice = 100 - 0 = 100 k

Therefore,

Q₃ = (0.5 kg)(1 kcal/kg.k)(100 k)

Q₃ = 50 kcal

4. VAPORIZATION OF WATER:

Now, the vaporization of water will occur at 100°C and the heat absorbed during this process will be:

Q₄ = m(Latent Heat of Vaporization of Water)

where,

Q₄ = heat Absorbed during vaporization of water = ?

Therefore,

Q₄ = (0.5 kg)(539 kcal/kg)

Q₄ = 269.5 kcal

5. RISE IN TEMPERATURE OF STEAM:

Now, the temperature of steam will be increased from 100°C to 110 °C. Heat absorbed during this process will be given as:

Q₅ = mC₅ΔT₅

where,

Q₅ = Heat absorbed while increasing temperature of steam = ?

m = mass of steam = 0.5 kg

C₅ = specific heat of steam = 0.48 kcal/kg k

ΔT₅ = change in temperature of ice = 110 - 100 = 10 k

Therefore,

Q₅ = (0.5 kg)(0.48 kcal/kg.k)(10 k)

Q₅ = 2.4 kcal

Hence, the total heat absorbed to change 0.5 kg of ice at - 10°C into steam at 110°C will be:

Q = Q₁ + Q₂ + Q₃ + Q₄ + Q₅

Q = 2.5 kcal + 39.85 kcal + 50 kcal + 269.5 kcal + 2.4 kcal

Q = 364.25 kcal

Answer:

i think its second law of motion.

Explanation:

Answer:

it’s the second law

Explanation:

Answer:

See the answer below

Explanation:

If you step on the brake of a car while driving, the frictional force between the tires of the car and the surface of the road increases in opposition to the motion of the car. Consequently, the car slows down.

If you release your foot from the brake pedal when the car is still at half speed, the frictional force reduces and the car speeds up a bit even without pressing the throttle. Eventually, the frictional force will slow down and stop the car if the throttle is not pressed.

Answer: positive

Explanation: because opposites attract and north=positive and south=negative the answer should be positive.

The polarity of the red tip of the compass needle must be at the north of the earth, since it points toward the south pole of the magnet.

Polarity of a magnet is defined as the orientation of both the north and south poles of the magnet in space.

Here,

We know that, the opposite poles attract.

The magnetic needle is arranged in a such a way that, the red tip of the magnetic compass needle is actually pointing towards the geographic north pole of the earth.

In order to point the compass needle towards the magnetic south pole, the south pole of the magnet must be located in the geographic north pole.

Hence,

The polarity of the red tip of the compass needle must be at the north of the earth, since it points toward the south pole of the magnet.

To learn more about polarity of magnet, click:

https://brainly.com/question/15329793

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Answer:

8

Explanation:

240 divided by 30 = 8

power is reffering to force

Answer:

An average net force of 5200 N is needed to stop the car

Explanation:

Cinematics and Dynamics

Cinematics describes the variables involved in the movement without dealing with its causes. There are four main concepts in cinematics: Velocity (or its scalar equivalent, the speed), acceleration, time, and displacement (or the scalar equivalent, distance).

The acceleration can be calculated by:

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

The initial speed is vo=28 m/s, it stops (vf=0) in t=10.5 seconds, thus the acceleration is:

[tex]\displaystyle a=\frac{0-28}{10.5}[/tex]

[tex]a = -2.67~m/s^2[/tex]

The acceleration is negative because the car loses speed.

Knowing the mass of the car m=1950 Kg, we can calculate the net force required to stop the car by using the formula:

F = m.a =1950*2.67

F = 5200 N

An average net force of 5200 N is needed to stop the car

Answer:

They're typically made up of three main parts: protons, neutrons and electrons. Think of the protons and neutrons as together forming a “sun”, or nucleus, at the centre of the system. The electrons orbit this nucleus, like planets. If atoms are impossibly small, these subatomic particles are even more so.

Explanation:

hope i helped.

Answer:

Atoms consist of a nucleus made of protons and neutrons orbited by electrons. ... We now know that atoms are made up of three particles: protons, neutrons and electrons — which are composed of even smaller particles, such as quarks.

Explanation:

Answer:

Weight. Recall that the acceleration of a free-falling object near Earth's surface is approximately g=9.80m/s2 g = 9.80 m/s 2 . The force causing this acceleration is called the weight of the object, and from Newton's second law, it has the value mg.

Explanation:

Answer:

4th one

Explanation:

Answer:

100 Watts

Explanation:

These equations are needed to work out the answer:

force: 10 kg* 2m/s= 20

work done: 20* 10m=200

power: 200/2=100

Answer:

B

Explanation:

Answer:

B

Explanation:

I had a feeling

Answer:

What I put- This will affect animals, the earth, and could affect future generations. Plastic also gets into the oceans causing sea creaters die by eating it.

Sample Answer- Problems that arise from the unavailability of natural resources and from environmental hazards will affect the generations that follow us.

Explanation:

Answer:

This will affect animals, the earth, and could affect future generations. Plastic also gets into the oceans causing sea creaters die by eating it.

Explanation:

Answer:

The thrust is  [tex]F = 7828.3 \  N [/tex]

Explanation:

From the question we are told that

   The speed of the jet aircraft is  [tex]v = 214 \ m/s[/tex]

    The rate at which the engine takes in air is [tex]\^ Q = 115 \ kg/s[/tex]

    The rate  at which the engine burns fuel is  [tex]\r m = 2.53 \ kg/s[/tex]

    The speed of the exhaust gases is  [tex]u = 276 \ m/s[/tex]

Generally the thrust of the engine is mathematically represented as

      [tex]F =[ \^ Q * ( u - v )] + (\r m * u)[/tex]

=>   [tex]F =[ 115 * ( 276  -  214 )]  + (2.53 * 276)[/tex]

=>   [tex]F = 7828.3 \  N [/tex]

Answer:

How much power is used if 350J of work is done when pushing a box for 5 seconds.

Explanation:

the answer is 70watts

Answer:

1.2N

Explanation:

f=m×a

m=3kg

a=.4m/s/s

3×.4=1.2

kg×m/s/s = N

Answer:

The value is  [tex]f = 0.05 \ Hz[/tex]

Explanation:

From the question we are told that

     The mass of the car is  [tex]m = 615 \ kg[/tex]

      The period of the circular motion is  [tex]T = 20 \ s[/tex]

      The radius  is [tex]r = 80 \ m/s[/tex]

Generally the frequency of the circular motion is  

       [tex]f = \frac{1}{T }[/tex]

=>    [tex]f = \frac{1}{ 20 }[/tex]

=>    [tex]f = 0.05 \ Hz[/tex]

Answer:

potential

Explanation:At this point the energy is stored in a form called potential energy. This means that the system has the potential to do work or to become active thanks here to the weight's position high above the lowest point of its swing.

Answer:

Electrical energy

Explanation:

Answer:

Explanation:

I hope this helps

Answer:Explanation:

Protons and neutrons have very similar mass, while electrons are far lighter, approximately 11800 times the mass. Protons are positively charged, neutrons have no electric charge, electrons are negatively charged. The size of the charges is the same, the sign is opposite.