Which of the following examples best represents an object with balanced forces acting upon it?

A - A boat accelerating through the water.
B - A book sitting at rest on a high shelf.
C- A wagon rolling down a steep hill.
D- A baseball thrown into the air.

Using Newtons Second Law:

F = m×a

F = (0.25 kg)(-2 m/s²)

F = -0.5 N

Answer:

here u go

Explanation:

Earth's rotation is the rotation of planet Earth around its own axis. Earth rotates eastward, in prograde motion. As viewed from the north pole star Polaris, Earth turns counterclockwise.

The earth has a magnetic field. It is much like a bar magnet. Imagine a gigantic bar magnet inside the Earth. But there is no giant magnet inside it.

To have a pretty good idea what earth's magnetic field is shaped like we imagine a bar magnet inside the earth.

The magnetic field is made by the motion of molten iron in earth's outer core.  The swirling motion of molten iron changes all the time. Therefore, the magnetic fields will also get change. Then, the magnet poles also move.

The North pole and the south pole are two geographic poles of earth.  These poles are the places on the earth's surface that earth's imaginary spin axis passes through.

There are two magnetic poles of the earth: North magnetic pole and South magnetic pole.

Earth's magnetic field is tilted a little bit. If we imagine that earth's magnetic field is made by a giant bar magnet. Then, the bar magnet would make an with earth's spin axis.

The geographic poles and the magnetic poles are not in the same place.

If we are standing at one magnetic poles then the magnetic field lines would be straight up and down.

Earth's magnetic field is a complex and dynamic phenomenon that is generated by the motion of molten iron in its outer core. The magnetic field extends far beyond the planet and is responsible for protecting Earth from harmful solar radiation and cosmic rays.

Earth's magnetic field is roughly dipolar in shape, meaning it has two main magnetic poles - north and south - and the field lines emerge from the north and re-enter at the south pole. The magnetic field has a strength of about 25-65 microteslas (μT) at the Earth's surface, and it extends for several tens of thousands of kilometers into space.

2. Where are Earth's magnetic poles?

Earth's magnetic poles are not fixed and are constantly moving due to the complex and dynamic nature of the planet's magnetic field. Currently, the north magnetic pole is located in the Arctic Ocean, close to Canada's Ellesmere Island, and the south magnetic pole is located in the Antarctic Ocean, near the coast of Antarctica.

3. Where is the magnet that causes Earth's magnetic field located? What is this magnet made of?

The magnet that causes Earth's magnetic field is not a physical magnet but rather a result of the motion of molten iron in the Earth's outer core. The outer core is a layer of liquid iron and nickel that surrounds the solid inner core. The motion of this molten iron generates electrical currents, which in turn create a magnetic field.

4. Does Earth's magnetic field move?

Yes, Earth's magnetic field is not static and is constantly changing due to the complex nature of the planet's interior. The magnetic poles are constantly moving and the strength of the magnetic field can vary over time. The magnetic field can also be influenced by external factors such as solar storms and changes in the solar wind. Scientists continue to study Earth's magnetic field to better understand its behavior and how it affects the planet.

Therefore, The magnetic field of the Earth is a complex and dynamic phenomenon caused by the movement of molten iron in its outer core. The magnetic field extends far beyond the planet and is in charge of shielding the planet from harmful solar radiation and cosmic rays.

To learn about cosmic rays click:

https://brainly.com/question/13960192

#SPJ3

Answer:

6.77m/s

Explanation:

Using the law of conservation of momentum

m1u1 + m2u2 = (m1+m2)v

m1 and m2 are the masses of the object

u1 and u2 are the velocities before collision

v is the final collision

Given

m1 = 300g  = 0.3kg

u1 = 6.0m/s

m2 = 10g = 0.01kg

u2 = 30m/s

Required

The bird's speed immediately after swallowing v

Substitute the given values into the formula

m1u1 + m2u2 = (m1+m2)v

0.3(6) + 0.01(30) = (0.3+0.01)v

1.8+0.3 = 0.31v

2.1 = 0.31v

v = 2.1/0.31

v = 6.77m/s

Hence the bird's speed immediately after swallowing is 6.77m/s

Answer:

The minimum coefficient of static friction required, µ = 0.10

Note. The question is incomplete. The complete question is given below:

While hauling a log in the back of a flatbed truck, a driver is pulled over by the state police. Although the log cannot roll sideways, the police claim that the log could have slid out the back of the truck when accelerating from rest. The driver claims that the truck could not possibly accelerate at the level needed to achieve such an effect. Regardless, the police write a ticket anyway and now the driver court date is approaching.

The log has a mass of m = 929 kg; the truck has a mass of M = 8850 kg. According to the truck manufacturer, the truck can accelerate from 0 to 55 mph in 23.0 seconds, but this does not account for the additional mass of the log. Calculate the minimum coefficient of static friction μs needed to keep the log in the back of the truck.

Explanation:

First, velocity in mph is converted to m/s

1 mph = 0.447 m/s

55 mph ≈ 24.6 m/s

The acceleration of the empty truck is a = v/t = 24.6 / 23 = 1.07 m/s²

Force that can be generated by the truck, F = ma

F = 8850kg * 1.07 m/s² = 9469.5 N

However, with the added mass of the log on it, the acceleration of the truck will become;

a = F / m = 9469.5 N / (8550+929)kg = 0.97 m/s²

Frictional force between the log and the truck = 0.97 m/s² * 929 kg = 901.13 N

Normal reaction on the truck due to the weight of the log, R = mg

R = 929 kg * 9.8m/s² = 9104.2 N

Coefficient of static friction, µ = F/R

µ = 901.13/9104.2

µ = 0.098 ≈ 0.10

Therefore, the minimum static friction required is µ = 0.10

Answer:

The fraction of the object that is below the surface of the water is ¹⁷/₂₀

Explanation:

Given;

specific gravity of the object, γ = 0.850

Specific gravity is given as;

[tex]specific \ gravity = \frac{density \ of the \ object}{density \ of \ water}\\\\0.85= \frac{density \ of the \ object}{1000 \ kg/m^3} \\\\density \ of the \ object = 850 \ kg/m^3[/tex]

Fraction of the object's weight below the surface of water is calculated as;

[tex]= \frac{850}{1000} \ \times\ 100\%\\\\= 85 \% \\\\= \frac{17}{20}[/tex]

Therefore, the fraction of the object that is below the surface of the water is ¹⁷/₂₀

Answer:

880J/kelvin

Explanation:

Q =MC ×change in t

c =C/m

C=Q/change in t

c= Q/ m× change in t

c = 26400 / 2.0 × 15

c = 880 J/kelvin

Answer:

S = 2461.53 [kJ]

Explanation:

The change in entropy in a process such as melting can be calculated by means of the following expression.

[tex]S=\frac{H*m}{T}[/tex]

where:

S = entropy [kJ]

H = fusion heat = 3.36*10¹ [J/kg]

m = mass = 0.02 [kg]

T = temperature in kelvin = 273 [K]

[tex]S = \frac{0.02*3.36*10^{1} }{(273+0)}\\S = 2461.53 [kJ][/tex]