Physics College

## Answers

**Answer 1**

**Answer:**

**Explanation:**

As no altitude or mass changed, the potential energy remained constant.

**The potential energy will stay the same as long as the book stays on the**

**table. **

Kinetic energy went from zero at rest to a positive value while moving, and then returned to zero when the book was at rest again.

**The kinetic energy increases as the book is pushed across the table.**

## Related Questions

A ball rolling down a hill with a speed of 8 m/s has 139 J of kinetic energy. What is it's mass in kg?

### Answers

**Explanation:**

Velocity of ball (v) = 8 m/sKinetic Energy (K.E) = 139 JMass (m) = ?

We know that,

• K.E = ½mv²

→ 139 = ½ × m × (8)²

→ 139 = ½ × m × 64

→ 139 = 1 × m × 32

→ 139 ÷ 32 = m

→ **4****.****3****4**** ****kg**** ****=**** ****m**

**Therefore****,**** ****mass**** ****in**** ****kg**** ****is**** ****4****.****3****4**** ****kg****.**

hey if you talk to me i will mark you as a brainliest and if you answer all my question

huh huh huh

### Answers

**Answer:**

**what**** ****will**** ****happen**** ****if**** ****i**** ****will**** ****answer**** ****ur**** ****questions****?**

**Explanation:**

**is**** ****there**** ****gonna**** ****be**** ****a**** ****bad**** ****thing**** ****o****r**** ****a**** ****good**** ****thing**

True or False. When Isaac’s father was a 100 God changed his name from Abram to Abraham.

### Answers

I believe this is false

objects want to ______ ___________ doing what they're __________ ____________ because they are "lazy." This is called __________.

### Answers

**Answer:**

**Explanation:**

Objects want to continue doing what they're already doing because they are "lazy." This is called inertia.

A baseball is hit with a speed of 27.0 m/s at an angle of 47.0 ∘ . It lands on the flat roof of a 10.0 m -tall nearby building. Part A If the ball was hit when it was 1.3 m above the ground, what horizontal distance does it travel before it lands on the building?

### Answers

**Answer:**

H = Vy t - 1,2 g t^2 formula for height of ball after t sec

H = 10 - 1.3 = 8.7 m

Vy = 27 sin 47 = 19.7 m/s vertical speed of ball

8.7 = 19.7 t - 9.8/2 t^2 height of ball after t sec

4.9 t^2 - 19.7 + 8.7 = 0 rearranging

[19.7 ± (388 - 170)^1/2] / 2 *4.9 = [19.7 ± 14.7] / 9.8 = .51 ,3.5 sec

.51 sec would be on the way up and 3.5 sec on the way down

Sx = 27 * cos 47 * 3.5 = 64.4 m around 200 ft seems reasonable

A gold fish weighing 13g has a speed of 8.8m/s. What is its Kinetic energy

### Answers

**Answer:**

0.47 J

**Explanation:**

Ram jumps onto a cement floor from a height of 1m and comes to rest in 0.1sec.

Then he jumps onto a sand floor from a height of 9m and comes to rest in 1sec.

Find the ratio of forces of cement floor and sand floor.

### Answers

**Answer:**

3/10 F.

**Explanation:**

Height ( h ) = 1m

Time taken ( t ) = 0.1 second

Height² ( h² ) = 9m

Time taken² ( t² ) = 1 second

Solution,

F = ma

= m ( v - u ) / t

= m √2gh / t

now,

F/F² = √h/h² × t/t²

F¹ = 3/10 F.

answer !!

how is the atomic mass determined?

### Answers

**Answer:**

Atomic mass is defined as the number of protons and neutrons in an atom, where each proton and neutron has a mass of approximately 1 amu (1.0073 and 1.0087, respectively). The electrons within an atom are so miniscule compared to protons and neutrons that their mass is negligible.

**Explanation:**

How do I solve this problem

### Answers

**Answer:**

it is light

**Explanation:**

the arrow that says light is on the glass it must be near from tungsten

a

A person throws a ball up into the air, and the ball falls back towar

would the kinetic energy be the lowest? (1 point)

at a point before the ball hits the ground

when the ball leaves the person's hand

o when the ball is at its highest point

at a point when the ball is still rising

### Answers

**Answer:**

**when the ball is at its highest point**

**Explanation:**

Provided the ball returns to where it was thrown. The velocity, and therefore kinetic energy, will be momentarily zero at the highest point of the throw.

How much energy is needed to change the temperature of 50g of water 15°c

### Answers

**Explanation:**

This question is not feasible. There is no way to calculate the energy needed because the question is missing the final temperature

3 materials that are denser than water and 3 that arent denser than water

### Answers

**Answer:**

denser than water:

1. clay

2. coins

3. rock

aren't denser than water

1. wood

2. sponge

3. apple

I need help with this question!

### Answers

**Answer:**

**Explanation:**

Conservation of momentum

In the x direction

2(15) + 2(-10) = 2(-5) + 2(vBfx)

vBfx = 10 m/s

In the y direction

2(30) + 2(5) = 2(20) + 2(vBfy)

vBfy = 15 m/s

**vBf = 10i + 15j**

KEi = ½(2)(15² + 30²) + ½(2)(-10² + 5²) = 1250 J

KEf = ½(2)(-5² + 20²) + ½(2)(10² + 15²) = 750 J

KEf - KEi = 750 - 1250 = **-500 J**

How is the çhocolate shell on the outside of the bar different from the ice cream on the inside?

### Answers

**Answer:**

Cake Crunch (Enriched Wheat Flour [Bleached Flour, Niacin, Reduced Iron, Thiamine Mononitrate, Riboflavin, Folic Acid]), Sugar, Vegetable Shortening [Partially Hydrogenated Soybean and Cottonseed Oil], Salt, Sodium Bicarbonate, Artificial Flavor, Soy Lecithin, Soybean Oil, Coconut Oil, Sugar, Chocolate Liquor, ...

the conduction of heat from hot body to cold body is an example of what thermodynamics process?

### Answers

**Answer:**

Heat flow

**Explanation:**

A model shows a machine that works using electric fields. What would this machine need for the electrical field to function properly

### Answers

It would need at least two charges interacting parts

) Water flows through the system shown below. Estimate the volumetric flow rate if friction

losses are negligible.

### Answers

The **volumetric flow rate** if friction is negligible = **0.00197 m³/sec**

Given data :

P₁ = 7 atm = **709.275 kPa**

P₂ = 1.5 atm = 151.988 kPa

**d₁ **= 0.74 cm = 0.0074 m

**d₂** = 1.20 cm = 0.0120 m

h = 82 m

density of water **( p ) **= 1000 kJ/m³

Estimate the volumetric flow rate

given that **friction losses** are negligible

V₁² - V₂² = [tex]\frac{2(P_{2} - P_{1}) }{p} + 2g(h )[/tex]

= 2( 151.988 - 709.275 ) + 2 * 9.81 * 82

= 2 ( - 557.287 ) + 1608.84

= - 1114.574 + 1608.84 = 494.266

∴ **V₁² - V₂²** = 494.266 ----- ( 1 )

Also given that:

volumetric** flow rate** ( Q ) = A₁V₁ = A₂V₂

= π / 4 ( 0.0074 )² * V₁ = π / 4 ( 0.0120 )² * V₂

= 0.000043 V₁ = 0.000113 V₂

∴ V₁ = 2.63 V₂

Back to **equation ( 1 ) **

( 2.63 v₂ )² - V₂² = 494.266

V₂² = ( 494.266 ) / 1.63

∴ V₂ = √303.23 = 17.41 m/sec

Therefore the **volumetric flow rate** ( Q )

Q = A₂V₂

= π / 4 * ( 0.0120 )² * 17.41

= **0.00197 m³/sec**

Learn more about **volumetric flow rate** : https://brainly.com/question/24356835

A crate is released on a frictionless plank inclined at angle q with

respect to the horizontal. Which of the following relationships is true?

(Assume that the x-axis is parallel to the surface of the incline.)

a. Fy = Fg

c. Fy = Fx

b. Fx = 0

d. none of the above

### Answers

**None **of the given options is correct based on the **relationship **for the **components **of the **crate's weight.**

The given parameter:

*Angle of inclination, = q*

The** vertical component** of the **force **on the crate is calculated as follows;

[tex]F_y = W \times cos(q)\\\\F_y = F_gcos(q)[/tex]

The **horizontal component** of the **crate **is calculated as follows;

[tex]F_x = F_g \times sin(q)\\\\F_x = F_g sin(q)[/tex]

Thus, we can conclude that **none **of the given options is correct based on the **relationship **for the **components **of the **crate's weight.**

Learn more about** forces on inclined weight** here: https://brainly.com/question/11351170

. Boa constrictor snakes have tiny pelvic girdles and leg bones within their bodies. Since these structures are not functional, they are called *

a. vestigial

b. analogous

c. maladaptive

d. hom*ologous

### Answers

Those **organic structures** that do not seem to play any important **biological function **in the organism that possesses them are known as **vestigial structures**.

What is a vestigial structure?

A **vestigial structure** is one that has **atrophied** or lost its original function throughout the course of **evolution**.

It generally refers to those **organic structures **that were useful at some point, but are now practically or totally** useless**.

These** structures** are preserved as an** inheritance **of the **evolutionary process**, because at some point an **ancestor** of the current species had that structure, which was **functional**, but it ceased to be important and would end up **atrophy**.

Therefore, we can conclude that **vestigial structures **are **structures **that some **organisms** still conserve as an **inheritance **from their ancestors but that, for some reason or another, are no longer useful for the functioning of the same.

Learn more about **vestigial structures** here: https://brainly.com/question/2141655

A ball has the energy to move 30 m/s with the mass of 5. What is the energy

### Answers

If an object is moving and has velocity it has kinetic energy. the kinetic energy of an object is the energy that it possesses due to its motion.

In my work I used the formula for kinetic energy to answer your question. Hope this helps.

Please help me answer the following question!

What is the momentum of a 750-kg Volkswagen Beetle when at rest?

Please give the Value and Unit

### Answers

**Answer:**

P = 0

**Explanation:**

Momentum is defined as the quentity of motion contained in a body. Mathematically, it can be defined as the product of mass and velocity. So, in order to determine the Volkswagen Beetle, at rest, we can use the simple formula, as follows:

where,

P = Momentum of Volkswagen Beetle = ?

m = Mass of Volkswagen Beetle = 750 kg

v = Velocity of Volkswagen Beetle = 0 m/s (since, it is at rest)

Therefore,

P =

The spring constant of Spring A is twice as great as the spring constant of Spring B. Both springs are stretched the same amount. How does the

force the Spring A applies compare to the force Spring B applies?

### Answers

**Answer:**

**FA = 2FB**

**Force on spring A is twice the Force on spring B**

**Explanation:**

F = kx

FB = (kB)x

FA = (kA)x

FA= (2kB)x

FA = 2(kB)x

**FA = 2FB**

The force [tex]F_A[/tex] needed to stretch spring A is going to be twice as much as the force [tex]F_B[/tex] needed to stretch spring B.

**Explanation:**

We know that the spring constants are related as

[tex]k_A = 2k_B[/tex]

The force [tex]F_A[/tex] needed to stretch spring A is given by

[tex]F_A = -k_Ax[/tex]

Also, the force [tex]F_B[/tex] needed to stretch spring is

[tex]F_B = -k_Bx[/tex]

Taking the ratio of the forces, we get

[tex]\dfrac{F_A}{F_B} = \dfrac{-k_Ax}{-k_Bx} = \dfrac{k_A}{k_B}[/tex]

Since [tex]k_A = 2k_B,[/tex] the equation above becomes

[tex]\dfrac{F_A}{F_B} = \dfrac{2k_B}{k_B} = 2[/tex]

or

[tex]F_A = 2F_B[/tex]

This shows that since the spring constant of spring A is twice as large as that of spring B, the force needed is going to be twice as large.

How far has a 15 kg object moved, when a force of 22 N is applied for 5 seconds if it started at 3 m/s?

### Answers

First start by finding the acceleration experienced by the force. Then use the acceleration and a suvat equation to solve for distance.

7. Which of the following explains how radiometric dating is used to estimate absolute

age.

a. By comparing how deep in the curst the radioactive material in a sample of rock

is, scientists can calculate the length of time since the rock formed.

b. By comparing the amount of organic material in a sample of rock, to the known

rate of decay of the parent rock, scientists can calculate the length of time since

the rock formed.

C. By comparing the amount of radioactive material in a sample of rock, to the

surrounding rocks, scientists can calculate the length of time since the rock

formed.

d. By comparing the amount of a radioactive material in a sample of rock, to the

know rate of decay of the parent rock, scientists can calculate the length of time

since the rock formed.

### Answers

**Answer:**

d.

**Explanation:**

Radiometric dating is a method of dating geological/ archaeological specimens by determining the relative proportions of particular radioactive isotopes present in a sample. Carbon dating is a form of radiometric dating, but, in choice b, you're not comparing the carbon to the rock. One would compare ¹⁴C levels within the organic compound, just as one would compare radioactive isotope levels in a rock.

A stone of mass m = 1.05 kg is released from a height of h = 2.1 m into a pool of water. At a time of t = 1.83 s after hitting the surface of the water, the stone's velocity has decreased by 50%.

What is the magnitude of the average force the stone experiences, in newtons, during the time t?

### Answers

**Answer:**

**Explanation:**

ignoring air resistance, the kinetic energy at water impact will equal the potential energy converted

½mv² = mgh

v = √(2gh)

v = √(2(9.81)2.1) = 6.4188... m/s

after impact, an impulse will result in a change of momentum.

There is a downward impulse due to gravity equal to the weight of the stone and an upward average force due to water resistance and buoyancy force.

FΔt = mΔv

(F - mg)Δt = m(vf - vi)

(F - mg) = m(vf - vi)/Δt

F = m(vf - vi)/Δt + mg

F = m((vf - vi)/Δt + g)

F = 1.05(((½(-6.4188) - -6.4188)/ 1.83) + 9.81)

F = 12.14198...

**F = 12.1 N**

The magnitude of the average force the stone experiences, will be 12.1 N.

What is force?

Force is defined as the push or pulls applied to the body. Sometimes it is used to change the shape, size, and direction of the body. Force is defined as the product of mass and acceleration. Its unit is Newton.

The **given **data in the problem is;

m is the stone mass = 1.05 kg

The height is h, = 2.1 m i

The time is, t = 1.83 s

Velocity decreased by 50%.

From the law of conservation of **energy **the** kinetic energy** is equal to the **potential energy;**

[tex]\rm \frac{1}{2} mv^2 = mgh \\\\ v = \sqrt{2gh}\\\\ v = \sqrt{2 \times 9.81 \times 2.1 } \\\\ v= 64188 \ m/sec.[/tex]

From Newton's second law of motion, the** impulsive force** is equal to the change in **momentum**;

[tex]\rm F \triangle T = m \traingle v \\\\ (F - mg) = \frac{v_f-v_i}{\triangle t } \\\\ F = \frac{v_f-v_i}{\triangle t } + mg \\\\ F =m\frac{v_f-v_i}{\triangle t + g} \\\\ F= 12.14 98 \\\\ F=12.1 N[/tex]

Hence the **magnitude **of the** average force** the stone experiences, will be** 12.1 N.**

To learn more about the **force **refer to the link;

https://brainly.com/question/26115859

the driver of a 2.0 × 10³ kg red car traveling on the highway at 45m/s slams on his brakes to avoid striking a second yellow car in front of him, which had come to of because locking ahead.After the brakes are applied a constant friction force of 7.5 × 10³ N acts on the car ignore air resistance.

a₎ Determine the least distance should the brakes be applied to avoid a collision with the other vehicle?

### Answers

**Answer:**

**Explanation:**

a = F/m = 7500/2000 = 3.75 m/s²

v² = u² + 2as

s = (v² - u²) / 2a

s = (0² - 45²) / (2(-3.75))

**s = 270 m**

Blonde hair is produced by inheriting double recessive alleles (bb) from one’s parents. What is the probability of their offspring having blonde hair?

plz help

### Answers

**Answer:**

25%

**Explanation:**

Ginny is snowboarding down a ski slope. Her total mass (including the snowboard) is 68.5 kg. When she reaches the bottom of the slope, she is moving at 6.55 m/s. The coefficient of friction between the snowboard and the ground is 0.088 . How fast will Ginny be moving 2 seconds after reaching the bottom of the slope?

1) 5.71 m/s

2)5.91 m/s

3)4.82 m/s

4)4.08 m/s

### Answers

**Answer:**

**Explanation:**

Assuming the run out at the bottom of the slope is horizontal

μ = Ff/N = Ff/mg

Ff = μmg

a = Ff/m = μmg/m = μg

v = u + at

v = u + μgt

v = 6.55 - 0.088(9.81)(2)

**v = 4.82 m/s**

After reaching the bottom of the slope, it will take a speed of **4.8m/s **to reach. So, the correct option is **(C)**.

What is Friction?

**Friction **is the force which opposes the relative motion of solid surfaces, fluid layers, and material elements that are sliding against each other. There are many types of friction like

Dry frictionFluid frictionLubricated friction Skin friction Internal friction

**Friction **can be expressed as

**Ff = μFN**

where, Ff is the force of friction (N)

μ is the coefficient of friction.

FN is the normal force

As per the **above equation**, it is actually the normal force, not the weight, which is responsible for **friction**.

For given information,

Assuming the bottom of the slope is horizontal

So, μ = Ff/N = Ff/mg

Ff = μmg

a = Ff/m = μmg/m = μg

v = u + at (u- initial speed, v= final speed, a= acceleration and t= time)

v = u + μgt (g= acceleration due to gravity)

u = 6.55 - 0.088(9.81)(2)

**u = 4.82 m/s**

Thus, after reaching the bottom of the slope, it will take a speed of **4.8m/s **to reach. So, the correct option is **(C)**.

Learn more about **Friction**, here:

https://brainly.com/question/13000653

#SPJ2

What can happen when untreated sewage water contaminates water?

### Answers

**Answer:**

**Health ****Effects ****↯**

Life-threatening human pathogens carried by sewage includecholera, typhoid and dysentery. Other diseases resulting from sewage contamination of water include schistosomiasis, hepatitis A, intestinal nematode infections, and numerous others.

**Explanation:**

BRAINLIEST PLEASE • •

︴︴

____

is xenon a pure substance

### Answers

[tex]\large\huge\green{\sf{Yes}}[/tex]