Physics College

## Answers

**Answer 1**

Answer:

a

[tex]H =212.6 \ J[/tex]

b

[tex]v = 7.647 \ m/s[/tex]

Explanation:

From the question we are told that

The child's weight is [tex]W_c = 287 \ N[/tex]

The length of the sliding surface of the playground is [tex]L = 7.20 \ m[/tex]

The coefficient of friction is [tex]\mu = 0.120[/tex]

The angle is [tex]\theta = 31.0 ^o[/tex]

The initial speed is [tex]u = 0.559 \ m/s[/tex]

Generally the normal force acting on the child is mathematically represented as

=> [tex]N = mg * cos \theta[/tex]

Note [tex]m * g = W_c[/tex]

Generally the frictional force between the slide and the child is

[tex]F_f = \mu * mg * cos \theta[/tex]

Generally the resultant force acting on the child due to her weight and the frictional force is mathematically represented as

[tex]F =m* g sin(\theta) - F_f[/tex]

Here F is the resultant force and it is represented as [tex]F = ma[/tex]

=> [tex]ma = m* g sin(31.0) - \mu * mg * cos (31.0)[/tex]

=> [tex]a = g sin(31.0)- \mu * g * cos (31.0)[/tex]

=> [tex]a = 9.8 * sin(31.0) - 0.120 * 9.8 * cos (31.0)[/tex]

=>[tex]a = 4.039 \ m/s^2[/tex]

So

[tex]F_f = 0.120 * 287 * cos (31.0)[/tex]

=> [tex]F_f = 29.52 \ N[/tex]

Generally the heat energy generated by the frictional force which equivalent tot the workdone by the frictional force is mathematically represented as

[tex]H = F_f * L[/tex]

=> [tex]H = 29.52 * 7.2[/tex]

=> [tex]H =212.6 \ J[/tex]

Generally from kinematic equation we have that

[tex]v^2 = u^2 + 2as[/tex]

=> [tex]v^2 = 0.559^2 + 2 * 4.039 * 7.2[/tex]

=> [tex]v = \sqrt{0.559^2 + 2 * 4.039 * 7.2}[/tex]

=> [tex]v = 7.647 \ m/s[/tex]

## Related Questions

If a 46 kg person walks up two floors in the Physics building (about 10 meters up), this person's potential energy has increased by _____ J.a. 1400 J b. 10,000 J. c. 1000 J. d. 100 J

### Answers

**Answer:**

**B.** 10000 J

**Explanation:**

The possible answers are not related to the statement at all. The correct statement is:

*If a 100 kg person walks up two floors in the Physics building (about 10 meters up), this person's potential energy has increased by:*

From definitions of work and gravitational potential, we get the following formula to calculate the change experimented in the person's potential energy after walking up two floors in the Physics building:

[tex]\Delta U_{g} = m\cdot g \cdot \Delta z[/tex] **(1)**

Where:

[tex]\Delta U_{g}[/tex] - Change in the gravitational potential energy, measured in joules.

[tex]m[/tex] - Mass of the person, measured in kilograms.

[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.

[tex]\Delta z[/tex] - Change in height, measured in meters.

If we know that [tex]m = 46\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex] and [tex]\Delta z = 10\,m[/tex], then the change in the gravitational potential energy is:

[tex]\Delta U_{g} = (100\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (10\,m)[/tex]

[tex]\Delta U_{g} = 9807\,J[/tex]

The choice that best approximates this answer is **B.**

The particle accelerator at CERN can accelerate an electron through a potential

difference of 80 kilovolts. Calculate

(a) The kinetic energy (in keV) of the electron

### Answers

Answer:

K.E = 1.28 × 10^-17 KeV

Explanation:

Given that a particle accelerator at CERN can accelerate an electron through a potentialdifference of 80 kilovolts.

To Calculate the kinetic energy (in keV) of the electron, let us first find the electron charge which is 1.60 × 10^-19C

The kinetic energy = work done

K.E = e × kV

Substitute e and the voltage into the formula

K.E = 1.60 × 10^-19 × 80

K.E = 1.28 × 10^-17 KeV

Therefore, the kinetic energy is approximately equal to 1.28 × 10^-17 KeV

giving brainliest to first one who gets this right

### Answers

a. Nitrogen, Oxygen,and Carbon Dioxide

hope im right but I dont really know

Robin would like to shoot an orange in a tree with his bow and arrow. The orange is hanging yf=5.00 myf=5.00 m above the ground. On his first try, Robin looses the arrow at v0=35.0 m/sv0=35.0 m/s at an angle of θ=30.0°θ=30.0° above the horizontal. The arrow has an initial height of y0=1.50 m,y0=1.50 m, and its tip is x=60.0 mx=60.0 m away from the target orange. Treating the arrow as a point projectile and neglecting air resistance, what is the height of the arrow once it has reached the horizontal position xx of the orange? Use g=9.81 m/s2g=9.81 m/s2 for the acceleration due to gravity.

### Answers

**Answer:**

h' = 55.3 m

**Explanation:**

First, we analyze the horizontal motion of the projectile, to find the time taken by the arrow to reach the orange. Since, air friction is negligible, therefore, the motion shall be uniform:

**s = vt**

where,

s = horizontal distance between arrow and orange = 60 m

v = initial horizontal speed of the arrow = v₀ Cos θ

θ = launch angle = 30°

v₀ = launch speed = 35 m/s

Therefore,

**60 m = (35 m/s)Cos 30° t**

**t = 60 m/30.31 m/s**

**t = 1.98 s**

Now, we analyze the vertical motion to find the height if arrow at this time. Using second equation of motion:

**h = Vi t + (1/2)gt²**

where,

Vi = Vertical Component of initial Velocity = v₀ Sin θ = (35 m/s)Sin 30°

Vi = 17.5 m/s

Therefore,

**h = (17.5 m/s)(1.98 s) + (1/2)(9.81 m/s²)(1.98 s)²**

**h = 34.6 m + 19.2 m**

**h = 53.8 m**

since, the arrow initially had a height of y = 1.5 m. Therefore, its final height will be:

**h' = h + y**

**h' = 53.8 m + 1.5 m**

**h' = 55.3 m**

why is it more painful to walk on gravel with your shoes off then on (3 marks please)

### Answers

**Answer:**

Because shoes protect our feet from some of the most harmful platforms

Gravel has some small pebbles on it sometimes (or other sharp objects)

Gravel is pretty hard.

What is the force used when a 7 kg bowling ball is rolled with an acceleration of 3 m /s2? Use the formula to find the force in Newtons (N): F = 7 kg × 3 m/s2

### Answers

**Answer:**

21 Newtons

**Explanation:**

Force= mass * acceleration

Force= 7 kg * 3 m/s^2

Force= 21 Newtons

A 1150 kg car is on a 8.70° hill.

Using X-Y axes tilted down the

plane, what is the y-component

of the weight?

### Answers

Answer:

Explanation:

y-component = - mgcos(8.7)

= - (1150)(9.81)cos(8.7)

= - 11151.69378

= - 11151.69 N

The **weight **of the **y-component is 11140.33N.**

**How to find the weight of the y-component?**

To find the weight of the **y-component**:

Given,

Car weight = 1150 kg

Anfle = 8.70 degree

**weight = mg **= 1150 * 9.8

= 11270 N

**Y-component** = **mg cos∅**

**=** 11270 * cos(8.70)

**= 11140.33N**

The aspect that pushes proper or left is referred to as the x-factor, and the **element **that pushes up or down is known as the** y-component.**

Learn more about **y-component **here: brainly.com/question/26700114

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9. What distance is a book from the floor if the book contains 196 Joules of potential energy and has a mass of 5 kg?

### Answers

**Answer:**

the book is 4 meters from the floor

**Explanation:**

Use the formula for potential energy:

U = m g h

196 J = 5kg 9.8m/s^2 h

h = 196 / (5*9.8 ) m

h =** 4 m**

Select all correct answers....Covalent compounds

### Answers

I know for sure that the third one is correct

1. It plays a vital role for self- expression and has been part of rituals

and religious gatherings.

B. Dance

A. Aerobic activity

C. Fitness D. Zumba

### Answers

**Answer:**

b.dance

**Explanation:**

don't know the explanation

At an air show a jet flies at speed 1500 km/h on a day when the speed of sound is 342 m/s. What is the angle of the shock cone

### Answers

Answer:

55 degrees

Explanation:

Given thatan air show a jet flies at speed 1500 km/h on a day when the speed of sound is 342 m/s.

From the question above, we can get the below parameters

Object speed (V) = 1500 km/h

Sound speed ( v) = 342 m/s

Convert km/h to m/s

(1500 × 1000)/3600

Jet speed V = 416.67 m/s

Let's first calculate the mash number M.

M = V/v

M = 416.67 / 342

M = 1.2183

Formula for the angle of the shock cone is reciprocal of mash number. That is,

Sin Ø = 1 / M

Sin Ø = 1 / 1.2183

Sin Ø = 0.8208

Ø = sin^-1(0.8208)

Ø = 55 degree

Therefore, the angle of the shock cone is approximately 55 degrees

pls help quick. the number line shows the starting and ending velocities for ball 1 what's the change in velocity of ball 1 calculate the value mathematically and check using the number line

### Answers

**Answer:**

The starting velocity for ball 1 is 1.00 meter/second. Its ending velocity is 0.25 meter/second.

The change in velocity for ball 1 is 0.25 – 1.00 = -0.75 meter/seconds

In the Bohr model of the hydrogen atom, an electron in the 1st excited state moves at a speed of 2.19 106 m/s in a circular path having a radius of 5.29 10-11 m. What is the effective current associated with this orbiting electron?

### Answers

**Answer:**

**I = 1.05x10⁻³ A**

**Explanation:**

By definition, an electric current is the rate of charge flow at a given time:

[tex] I = \frac{q}{t} [/tex]

Where:

q: is the electrons charge = 1.602x10⁻¹⁹ C

t: is the time

In a circular motion, the time is given by:

[tex] t = T = \frac{2\pi}{\omega} = \frac{2\pi}{v/r} = \frac{2\pi r}{v} [/tex]

Where:

ω: is the angular speed = v/r

v: is the speed = 2.19x10⁶ m/s

r: is the radius = 5.29x10⁻¹¹ m

[tex] t = \frac{2\pi r}{v} = \frac{2\pi 5.29 \cdot 10^{-11} m}{2.19 \cdot 10^{6} m/s} = 1.52 \cdot 10^{-16} s [/tex]

Now, the effective current is:

[tex] I = \frac{q}{t} = \frac{1.602 \cdot 10^{-19} C}{ 1.52 \cdot 10^{-16} s} = 1.05 \cdot 10^{-3} A [/tex]

**Therefore, the effective current associated with this orbiting electron is 1.05x10⁻³ A.**

I hope it helps you!

which state can you infer that average home prices are the highest? Florida California Texas New York

### Answers

**Answer:**

California

**Explanation:**

just took the test

The state you can infer where **average **home prices are the highest is **California. Option B. **This is further explained below.

What is an average home price?

Generally, an average home price refers to a **cumulative** average to the house or** home pricing **in a state.

In conclusion, **California **has the highest average home prices highest in America.

Read more about **House**

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What is the wavelength of light falling on double slits separated by 2.00 μm if the third-order maximum is at an angle of 60.0∘?

### Answers

**Answer:**

λ = 5.773 x 10⁻⁷ m = 577.3 nm

**Explanation:**

In order to solve this problem we will use the grating equation:

**mλ = d Sin θ**

where,

m = order = 3

λ = wavelength of light = ?

d = slit separation = 2 μm = 2 x 10⁻⁶ m

θ = angle = 60°

Therefore,

**(3)λ = (2 x 10⁻⁶ m)Sin 60°**

**λ = 1.732 x 10⁻⁶ m/3**

**λ = 5.773 x 10⁻⁷ m = 577.3 nm**

An object moves at constant speed in a circle. Which of the following is true:

A. A net force in the direction of motion acts on the object.

B. A net force pointing away from the center of the circle acts on the object.

C. A net force pointing towards the center of the circle acts on the object.

D. The net force acting on the object is zero.

### Answers

The answer to your question is B

Friction that occurs in gases and liquids is called

### Answers

The answer is fluid friction

Why are the coral reefs suffering? (site 2) explain

### Answers

**Answer:**

bcuz ov yo fat mamma

**Explanation:**

**Answer:**

Water pollution

**Explanation:**

Which of the following requires the expenditure of more work?

a. Lifting a 110 newton [N] weight a height of 3 meters [m].

b. Exerting a force of 60 pounds-force [lbf] on a sofa to slide it 30 feet [ft] across a room.

### Answers

**Answer:**

The correct answer is option B

**Explanation:**

Step one:

given data

a. force F= 110N

distance s= 3meters

we know that work= Force* distance

work= 110*3

Work= 330Joules

Step two:

data

Force= 60 pounds

distance= 30 ft

convert pounds to Newton

1 pound= 4.44822N

60 pounds= 60*4.44822

=266.9N

convert ft to meteres

1 ft = 0.3048meter

30ft= 0.3048*30

=9.144N

we know that work= Force* distance

work= 266.9N*9.144N

Work= 2440.53Joules

Mr Jones launches an arrow horizontally at a rate of 40m/s off of a 78.4 m cliff towards the south, how far south does the arrow travel. (Step 2, you need the previous questions answer to answer correctly

a. 118.4 m south

b 1936 m south

C 2 m south

d 640 m south

### Answers

Answer:c

Explanation:its the answer because its the answer

What is the acceleration of gravity, in m/s2, on the surface (or outer limit) of Venus? The mass of Venus is 4.87 1024 kg and its radius is 6.05 106 m.

### Answers

**Answer:**

8.9 m/[tex]s^{2}[/tex]

**Explanation:**

From Newton's law of universal gravitation,

F = [tex]\frac{GMm}{R^{2} }[/tex] .............. 1

and from Newton's second law of motion,

F = mg ........... 2

Equating the two expression,

mg = [tex]\frac{GMm}{R^{2} }[/tex]

g = [tex]\frac{GM}{R^{2} }[/tex]

Given that: mass of Venus = 4.87 x [tex]10^{24}[/tex] Kg, radius = 6.05 x [tex]10^{6}[/tex] and G = 6.67 x [tex]10^{-11}[/tex] N[tex]m^{2} Kg^{-2}[/tex]

Thus;

g = [tex]\frac{6.67*10^{-11}*4.87*10^{24} }{(6.05*10^{6} )^{2} }[/tex]

= [tex]\frac{3.24829*10^{14} }{3.66025*10^{13} }[/tex]

= 8.87450

g = 8.9 m/[tex]s^{2}[/tex]

the acceleration of gravity on the surface of Venus is 8.9 m/[tex]s^{2}[/tex].

Mr Johnson launches an arrow horizontally at a rate of 40m/s off of a 78.4 m cliff towards the south, how much time does it take before the arrow hits the ground below (step 1 of a quesiton will need this answer for a future question)

a 2 seconds

b. 1 second

c.4 seconds

d 19.6

### Answers

Answer:c

Explanation:

Which statement best describes energy and matter in a closed system? (2 po

O Energy and matter flow into and out of the system.

Energy can flow into and out of the system but matter cannot.

Energy and matter are contained within a closed system.

O There is no energy in a closed system; there is matter.

### Answers

**Answer:**

Energy can flow into and out of the system but matter cannot.

**Explanation:**

In a closed system, energy can flow in and out of the system but matter cannot.

A closed system prevents double way flow of matter. A closed system conserves matter.

For an isolated system, energy and matter cannot flow out of the system.

For open systems, energy and matter can flow out of the system.

Such systems are used for certain thermodynamics experiment.

An object accelerates 12.0 m/s2 when a force of 6.0 newtons is applied to it. What is the mass of the object?

### Answers

**Answer:**

0.5 kg

**Explanation:**

The mass of the object can be found by using the formula

[tex]m = \frac{f}{a} \\ [/tex]

f is the force

a is the acceleration

From the question we have

[tex]m = \frac{6}{12} = \frac{1}{2} \\ [/tex]

We have the final answer as

0.5 kg

Hope this helps you

1. When asteroids collided some of the broken materials fall into Earth's orbit. What do

astronomers call the debris when it hits planet Earth?

(2 Points)

meteors

meteoroids

meteorites

metabots

### Answers

i believe it is meteoroids

Before they meet Earth -- meteoroids

While they're falling -- meteors

After they hit the ground -- meteorites

I WILL GIVE BRAILYEST!!! What is the mass of an object moving at a velocity of 5 m/s if the momentum of the object is 50 kg•m/s?

a. 250 kg

c. 10 Kg

b. .002 Kg

d. 45 Kg

### Answers

**Answer:**

a. 250kg I think it's the right answer. hope it helps:)

**Answer:**

C.10

**Explanation:**

because when you divide 50 divided by 5 = 10

Experiment: Gravity

Potential Energy = Force x Distance

To show you how this works, study the following example.

If the washers had a mass of 2 grams, and since the force due to gravity in the metric system is 9.8 m/sec2, the weight would be:

W = mass (kg) x gravity

W = 0.002 kg x 9.8 = 0.0196 Newton's. The Newton (N) is the measure of force (or weight here) in the metric system.

The next phase of the computation is to determine the difference in potential energy between where the washers originally started from and the energy of the new position. If the washers were originally 1 meter from the floor or desktop, and the magnet raised them 1 centimeter, the difference in distance raised will be 1 cm, or 0.01 m. Therefore, the potential energy change will be:

Force x Distance = Potential Energy

(0.0196 N) x (0.01 m) = 0.000196 Nm (or Joules)

The magnet is changing the potential energy of the washers by 0.000196 J, or in scientific notation:

1.96 x 10-4 J.

### Answers

**Answer: the washer would slow down depending on how strong the magnet is even though the gravitational pull is the same. the change would be .6**

**Explanation: i don't really get it**

What is gravitonal force

### Answers

**Answer:**

its something that hold the air for forceing liy by the exgen

**Explanation:**

HELP ASAP!!!

Which graph shows the change in velocity of an object in free fall?

### Answers

**Answer:**

the graph that show Change in velocity is no A

The** graph** that showing the velocity with respect to time for a free falling body is figure **C **where, the downward** velocity** will be higher due to the acceleration due to **gravity**.

What is velocity?

**Velocity** of a moving body is the measure of the** distance** covered per unit** time**. Thus, it is the ratio of distance to the time. Velocity is expressed in the units of Km/h, m/s. miles/h, ft./s etc.

The rate of change of velocity is called **acceleration**. The acceleration by the force of a gravitational field is called acceleration due to gravity g having the value 9.8 m/s².

The velocity - time graph shows a diagonal relation for a free falling body. A** free falling** body is initially at rest and falls downward with the **negative velocity **with the acceleration due to gravity. Therefore, figure B shows the change in velocity of a free falling body.

To find more on **velocity**, refer here:

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what are the formulae of momentun and their time of use

### Answers

**Answer:**

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