What does it mean when work is positive?

Answers

Answer 1
Both positive work and negative work have meaning: Positive work follows when the force has a component parallel to the displacement. Positive work adds energy to a system. Negative work follows when the force has a component opposite or against the displacement.

Related Questions



005 (part 1 of 2) 10.0 points

A runner is jogging in a straight line at a

steady vr= 8.5 km/hr. When the runner is

L=6.4 km from the finish line, a bird begins

flying straight from the runner to the finish

line at vý= 17 km/hr (2 times as fast as the

runner). When the bird reaches the finish

line, it turns around and flies directly back to

the runner

What cumulative distance does the bird

travel? Even though the bird is a dodo, as-

sume that it occupies only one point in space

(a "zero" length bird). travels in a straight

line, and that it can turn without loss of

Speed

Answers

Answer:

7.53 km

Explanation:

We at given;

Speed of runner; v_r = 8.5 km/hr

Speed of bird; v_y = 17 km/hr

L = 6.4 km

We know that; time = distance/speed.

We are told that the bird starts from 6.4 km from the start and that it flies back to meet the runner after it reaches the finish line. If the total distance back to the runner is x, it means bird distance is 6.4 + (6.4 - x) = 12.8 - x

Thus;

Time of bird(t_y) = (12.8 - x)/17

Thus,

Time of runner(t_r) = x/8.5 hr

To find x, we have to equate the times of the runner and the bird.

Thus;

x/8.5 = (12.8 - x)/17

Multiply both sides by 17 to get;

2x = 12.8 - x

2x + x = 12.8

3x = 12.8

x = 12.8/3

x = 4.27 km

Thus, cumulative distance traveled by bird is; 12.8 - 4.27 = 7.53 km

Opal is making a list of the uses of electromagnetic radiation. Which of the following should Opal NOT include in her list?

A. A man using a microwave to boil water

B. A submarine using sonar to locate a ship

C. A girl using a remote control to change television channels

D. A hospital using an X-ray machine to take a picture of a broken bone

Answers

Answer:

A.

Explanation:

A man using a microwave to boil water

Answer:

d

Explanation:

A sample contains 20 kg of radioactive material. The decay constant of the material is 0.179 per second. If the amount of time that has passed
is 300 seconds, how much of the of the original material is still radioactive? Show all work

Answers

Answer:

There are [tex]9.537\times 10^{-23}[/tex] kilograms of radioactive material after 300 seconds.

Explanation:

From Physics we know that radioactive materials decay at exponential rate, whose differential equation is:

[tex]\frac{dm}{dt} = -\lambda\cdot m[/tex] (1)

Where:

[tex]\frac{dm}{dt}[/tex] - Rate of change of the mass of the radioactive material, measured in kilograms per second.

[tex]m[/tex] - Current mass of the radioactive material, measured in kilograms.

[tex]\lambda[/tex] - Decay constant, measured in [tex]\frac{1}{s}[/tex].

The solution of the differential equation is:

[tex]m(t) = m_{o}\cdot e^{-\lambda\cdot t}[/tex] (2)

Where:

[tex]m_{o}[/tex] - Initial mass of the radioactive material, measured in kilograms.

[tex]t[/tex] - Time, measured in seconds.

If we know that [tex]m_{o} = 20\,kg[/tex], [tex]\lambda = 0.179\,\frac{1}{s}[/tex] and [tex]t = 300\,s[/tex], then the initial mass of the radioactive material is:

[tex]m(t) = (20\,kg)\cdot e^{-\left(0.179\,\frac{1}{s} \right)\cdot (300\,s)}[/tex]

[tex]m(t) \approx 9.537\times 10^{-23}\,kg[/tex]

There are [tex]9.537\times 10^{-23}[/tex] kilograms of radioactive material after 300 seconds.

The average velocity of an object over 6.0 seconds interval is 2 m/s what is the total distance traveled and M by the object doing this time interval

Answers

Answer:

The answer is 12 m

Explanation:

The distance covered by an object given it's velocity and time taken can be found by using the formula

distance = velocity × time

From the question we have

distance = 2 × 6

We have the final answer as

12 m

Hope this helps you

it is harmful to settle near the airport why

Answers

Yes, plane accidents can happen near you, it can harm your property and cause a disaster.

What would be the y-component of a velocity vector that had a
magnitude of 37m/s in a direction 30° from the x-axis?

Answers

Answer:

18.5 m/s

Explanation:

Just did it on EdPuzzle

The y-component of a velocity vector that had a magnitude of 37 m / s in a direction 30° from the x - axis would be 18.5 m / s .

What is a vector quantity?

The quantities that contain the magnitude of the quantities along with the direction are known as the vector quantities.

Examples of vector quantities are displacement, velocity acceleration, force, etc.

As given in the problem we have to find out the y-component of a velocity vector that had a magnitude of 37 m / s in a direction 30° from the x - axis.

The y-component of a velocity vector = 37 × sin 30

                                                                   = 18.5 m / s

Thus , y-component of a velocity vector that had a magnitude of 37 m / s in a direction 30° from the x - axis would be 18.5 m / s.

To learn more about the vector quantity here , refer to the link given below ;

https://brainly.com/question/15516363

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explain what happens when particles collide

Answers

Answer

they transfer energy

What is an electromagnetic wave?

A. An induced electric current
B. Vibrating electric and magnetic fields
C. Oscillating electric current
D. An electromagnet

Answers

I think it is B. Sorry if I’m wrong

for which colour of light is. the index of refraction of glass largest​

Answers

Answer:

don't know sorry for the irreverent answer..

Answer:

The index of refraction varies with frequency, it doesn't change as light travels from one medium to another, As violet colour has the shortest wavelength and so the refractive index is maximum for it.

Please help me fast

Answers

Answer:

b I think. sorry if it's wrong

What allows us to categorize rocks into the three rock types: Igneous, Sedimentary, and Metamorphic?
Whether or not the rock melts
Involvement of sediment
Process of formation
O Magma or weathering.

Answers

Answer:process of formation

Explanation:

A 3kg ball moving at 8 m/s strikes a 2kg ball at rest,if the collision is elastic,what is the speed of the lighter ball if the heavier ball moves at 2m/s in the opposite direction

Answers

Answer:

Speed of lighter ball is 4 m/s.

Explanation:

Applying the principle of conservation of linear momentum,

momentum before collision = momentum after collision.

[tex]m_{1}[/tex][tex]u_{1}[/tex] + [tex]m_{2}[/tex] [tex]u_{2}[/tex] = [tex]m_{1}[/tex][tex]v_{1}[/tex] - [tex]m_{2}[/tex][tex]v_{2}[/tex]

[tex]m_{1}[/tex] = 3 kg, [tex]u_{1}[/tex] = 8 m/s, [tex]m_{2}[/tex] = 2 kg, [tex]u_{2}[/tex] = 0 m/s ( since it is at rest), [tex]v_{1}[/tex] = 2 m/s, [tex]v_{2}[/tex] = ?

(3 x 8) + (2 x 0) = (8 x 2) - (2 x [tex]v_{2}[/tex])

24 + 0 = 16 - 2[tex]v_{2}[/tex]

2[tex]v_{2}[/tex] = 16 - 24

2[tex]v_{2}[/tex] = -8

[tex]v_{2}[/tex] = [tex]\frac{-8}{2}[/tex]

   = -4 m/s

This implies that the light ball moves at the speed of 4 m/s in the opposite direction of the heavier ball after collision.

Which of the following equations is balanced?

a. 2Al2O3 -----> 3Al + 3O2
b. 3Al2O3 -----> 3Al + 2O2
c. 2Al2O3 -----> 4Al + 3O2
d. 2Al2O3 -----> Al + 3O2

Answers

Answer: c

Explanation:

The way to check which one is the correct one is to simply multiply and see if there are the same number of atoms in both sides for each element.

a. 2×2 atoms of Al ≠ 3×1 atoms of Al

2×3 atoms of O = 3×2 atoms of O

BOTH MUST BE EQUAL FOR IT TO BE ADJUSTED!!!!!

b. 3×2 atoms of Al ≠ 3×1 atoms of Al

3×3 atoms of O ≠ 2×2 atoms of O

c. 2×2 atoms of Al = 4×1 atoms of Al

2×3 atoms of O = 3×2 atoms of O

BOTH ARE EQUAL, CORRECT ANSWER!!!

d. 2×2 atoms of Al ≠ 1×1 atoms of Al

2×3 atoms of O = 3×2 atoms of O

Lead-202 has a half-life of 53,000 years. How long will it take for 15/16 of a sample of lead-202 to decay?
106,000 years
159,000 years
212,000 years
265,000 years
(Thank you very much :L)

Answers

Answer:

C. 212,000 years

Explanation:

believe me it's correct.....and you're welcome :)

is the force that opposes the motion and therefore, tries to stop
or slow down a moving body.
e fuole​

Answers

Answer:

Friction is the force between an object in motion and the surface on which it moves. Friction is the external force that acts on objects and causes them to slow down when no other external force acts upon them. Inertia is the tendency of a body in motion to remain in motion.

Answer:

Explanation:

Friction is the drive between an object in motion and the surface on which it moves. Friction is the outside constrain that acts on objects and causes them to moderate down when no other outside drive acts upon them.

The south pole of one bar magnet is near the south pole of another bar magnet. What happens between the magnets?

A. They attract each other.
B. They twist toward each other.
C. They neither attract nor repel each other.
D. They repel each other.

PLEASE HELP!!!!!!!!!!​

Answers

the answer would be D

The south pole of one bar magnet brings near the south pole of another bar magnet, they repel each other. Therefore, option (D) is correct.

What are the magnets?

A magnet can be defined as an object which is capable of producing a magnetic field and attracting unlike poles and repelling like poles. When a magnet dropped in iron filings, the iron filings cling to the end of the magnet as the attraction is maximum at the ends of the magnet.

Magnetic poles always exist in pairs whenever a magnet is suspended freely in the air, and always points in the north-south direction. The pole pointing towards the geographic north is called the North Pole and the pole pointing towards the geographic south is called the South Pole.

Similar poles of a magnet repel while unlike poles attract each other. The magnetic force between the two magnets is higher when the distance between these magnets is lesser. There are three types of magnets which are Permanent magnets, Temporary magnets, and electromagnets.

Learn more about magnets, here:

https://brainly.com/question/3617233

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The SI unit of average speed m.s. True or False. But is there difference between m/s and m.s.​

Answers

Answer:

false

Explanation:

there is difference in m/s and m.s

Convert 14 minutes to seconds.
(What unit do we want)

1. Seconds
2. Minutes

Answers

Answer:

Seconds...

Explanation:

Can someone Plzzz help meee.

Answers

solid...............

On Planet X, an astronaut has maximum walking speed of 1.9 m/s. The astronaut's legs are each 1.3 m long. What is the constant of acceleration due to gravity on Planet X?

A. 8.3 m/s2
B. 2.8 m/s2
C. 3.8 m/s2
D. 1.1 m/s2

Answers

Answer:

Acceleration due to Gravity:

Explanation:

Here g is acceleration due to gravity. So C. 3.8 m/s2

The planet Jupiter is about 300 times as massive as Earth, but an object on its surface would weigh only 2.5 times as much as it would on earth. Can you come up with an explanation?

Answers

Answer:

here you go

Explanation:

so it might seem that a body on the surface of Jupiter would weigh 300 times as much as on Earth. ... But the radius of Jupiter is about 10 times that of Earth, weakening gravity by a factor of 100, resulting in 3 times its Earth weight.

What is the net force on this box?

Answers

Answer:

I believe 0

Explanation:

this is due to the fact that the box will not move anywhere the forces are canceling themselves out.  

Please identify the type of inference happening at letter A and the type of interference happening at letter B. If this was a sound wave, which (A or B) do you think would be louder and why?

Answers

Answer:

B i think

Explanation:

B because it travels in the same wavelentgh.............

[tex]gjkrejktg[/tex]

Type A is constructive interference and Type B wave gives destructive interference. The constructive interference would be louder.

What is interfernece?

Interference can be described as a natural phenomenon that occurs at every place and at every moment. Interference can be defined as the phenomenon in which two waves superpose to produce the resultant wave of the lower, higher, or same amplitude. Light waves are produced randomly by most of the sources.

The interference of light from the soap bubble which reflects colors when illuminated by a light source. The starting point of the wave produced may be a maximum or a minimum,  and there is no way to predict which phase the wave will start.

Interference can either be constructive interference or destructive interference. Constructive interference occurs when the crest of one wave falls on the crest of another wave and the amplitude is maximum.

In destructive interference, when the crest of one wave falls on the trough of another wave and the amplitude is minimum. The phase and displacement of these waves are not the same.

Learn more about interference, here:

https://brainly.com/question/22320785

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What is the average acceleration of a tennis ball that has an initial velocity of 6.0 m/s [E] and a final velocity of 7.3 m/s [W], if it is in contact with a tennis racket for 0.094 s?

Answers

Given :

The average acceleration of a tennis ball that has an initial velocity of 6.0 m/s.

and a final velocity of 7.3 m/s.

It is in contact with a tennis racket for 0.094 s

To Find :

The average acceleration of the tennis ball.

Solution :

We know, average acceleration is given by :

[tex]a_{avg}=\dfrac{Final \ velocity-Initial\ velocity}{Time\ Taken}\\\\a_{avg}=\dfrac{7.3-6.0}{0.094}\ m/s^2\\\\a_{avg}=13.83\ m/s^2[/tex]

Therefore, average velocity is given by 13.83 m/s².

Hence, this is the required solution.

A submarine is built to dive to a depth of 90 m where the pressure in the water is about 1 MPa. The engineers want to build a window in the submarine, but the window can only take a force of 10 kN safely. What is the largest surface area window that can be used?

Answers

Answer:

The largest surface area window that can be used is [tex]A=0.01\ m^2[/tex]

Explanation:

Pressure

The pressure is defined as force per unit area. The SI unit for pressure is the Pascal (Pa), defined as Newton per square meter.

If a force F acts on a surface area A, the pressure is calculated as:

[tex]\displaystyle P=\frac{F}{A}[/tex]

The pressure at a depth of 90 m is P=1 Mpa= 1,000,000 Pa and the submarine's window can only take a force of F=10 kN=10,000 N.

We need to calculate the largest surface area of the window. We can solve the equation for A:

[tex]\displaystyle A=\frac{F}{P}[/tex]

Substituting:

[tex]\displaystyle A=\frac{10,000}{1,000,000}[/tex]

[tex]A=0.01\ m^2[/tex]

The largest surface area window that can be used is [tex]\mathbf{A=0.01\ m^2}[/tex]

Does water pressure depend on the total amount of water present?

(Will pick brainliest)

Answers

Answer:

No, because pressure is determined by force and the area over which that force acts.

Explanation:

A diver runs horizontally off the end of a diving board with an initial speed of 1.95 m/s. If the diving board is 2.00 m above the water, what is the diver's speed just before she enters the water

Answers

Answer:

V = 6.56 m/s

Explanation:

in order to find the speed of the diver before she enters we need to find the vertical component of its final velocity by using 3rd equation of motion:

2gh = Vy² - V₀y²

where,

g = 9.8 m/s²

h = height = 2 m

Vy = Vertical Component of Final Velocity = ?

V₀y = Vertical Component of Initial Velocity = 0 m/s

Therefore,

2(9.8 m/s²)(2 m) = Vy² - (0 m/s)²

Vy = √39.2 m²/s²

Vy = 6.26 m/s

Assuming negligible air friction, the x-component of the final velocity will be the same as the initial velocity:

Vₓ = V₀ₓ = 1.95 m/s

Hence, the final velocity will be:

V = √(Vₓ² + Vy²)

V = √[(1.95 m/s)² + (6.26 m/s)²]

V = 6.56 m/s

A bugatti chiron travels 116 m/s for 10 seconds.how far did it travel

Answers

Answer:

V=  1,160 m

Explanation:

formula:

            V=  V*  T

remplazamos:

V= 116m /s * 10s

V=  1,160 m

Answer:

V=  1,160 m

Explanation:

A water tank is filled with up to 3.5 m height.Calculate the pressure given by the tank at its bottom​

Answers

Answer:

96.04Pa

Explanation:

height=3.5m

gravity=9.8%

density=9.8/3.5

=2.8

Preassure=h×g×d

=3.5×9.8×2.8

=96.04Pa

What is the current in the 10.0 resistor?

Answers

Answer:

12.0V

12.0V

Explanation:

.

.

.

.

.

.

.

.

.

.

.

Answer:

2.00 A

Explanation:

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