A box with mass of 2 kg is pushed directly horizontally over a horizontal surface (with friction) at a constant speed of 10 m/s. The force of the push is 60 N. How much thermal energy is generated pushing the box a distance of 15 m

Explanation:

Let 'F' be force acting perpendicularly, 'A' be the area and 'P' be the pressure exerted.

Then,

Pressure is directly proportional to the the force acting perpendicularly i.e.

P ∝ F ............. (i)

Pressure is inversely proportional to the area on which force acts i.e.

P ∝ 1/A ........... (ii)

Combining equations (i) and (ii),

P ∝ F/A

or, P = K × F/A [where K is a constant]

If F is 1N, A is 1m² and P is 1 N/m², then K is 1.

So, P = F/A proved...

Answer:

The name of the force is elastic (spring) force

Explanation:

The elastic force which is the restoration force of an elastic (spring like) object that tries to return to its initial non-stretched state built up by the pulling of the bow by the archer (using the muscles) pushes on the arrow which the archer releases the same time he leaves the bow string, and the arrow flies in the direction already pointed by the archer

The arrow ultimately falls down due to gravity forces that acts on all objects within the Earths gravitational field. However due to the speed of constant horizontal speed of the arrow and increasing downward speed of the due to the gravity force, the falling of the arrow looks disappointing.

Answer:

Explanation:

It is the case of perfectly elastic collision . So we shall apply formula of velocity after collision as follows .

Let  m₁ and m₂ be the mass colliding with velocity u₁ and u₂ and their velocity become v₁ and v₂ after collision .

[tex]v_1=\frac{(m_1-m_2)u_1 }{m_1+m_2)} +\frac{2 m_2u_2}{(m_1+m_2)}[/tex]

Putting the values

[tex]v_1=\frac{ (.30-.80).40 }{( .30+.80)} +\frac{2\times .80\times(-.15) }{(.30+.80 )}[/tex]

= - 0.4 m /s

So direction of .30 kg mass will be reversed .

[tex]v_2=\frac{ ( m_2-m_1) u_2 }{( m_1+m_2)} +\frac{2 m_1u_1}{(m_1+m_2)}[/tex]

putting the values

[tex]v_2=\frac{ ( .80-.30)(-.15) }{( .30+.80)} +\frac{2 \times.30\times.40}{(.30+.80)}[/tex]

= .15 m /s

The direction of .80 kg will become from left to right ie its direction will be reversed .

b ) Minimum amount of kinetic energy will be at the position when they move with common velocity

common velocity

v = .3 x .4 - .8 x .15 / (.3 + .8)

= 0

c )

Missing energy is stored as elastic potential energy in the spring .

Answer:

The impulse exerted by one cart on the other has a magnitude of 4 N.s.

Explanation:

Given;

mass of the first cart, m₁ = 2 kg

initial speed of the first car, u₁ = 3 m/s

mass of the second cart, m₂ = 4 kg

initial speed of the second cart, u₂ = 0

Let the final speed of both carts = v, since they stick together after collision.

Apply the principle of conservation of momentum to determine v

m₁u₁ + m₂u₂ = v(m₁ + m₂)

2 x 3 + 0 = v(2 + 4)

6 = 6v

v = 1 m/s

Impulse is given by;

I = ft = mΔv = m(

The impulse exerted by the first cart on the second cart is given;

I = 2 (3 -1 )

I = 4 N.s

The impulse exerted by the second cart on the first cart is given;

I = 4(0-1)

I = - 4 N.s (equal in magnitude but opposite in direction to the impulse exerted by the first).

Therefore, the impulse exerted by one cart on the other has a magnitude of 4 N.s.

Answer:

The sound travels differently in different medium according the density of the medium.

Explanation:

The sound travels faster in dense medium and can be heard by the vibration of the bone present in the ear. The ear plugs reduce the sound intensity in both medium water and on land (air).

In air the sound is not heard properly due to the earplugs that stops the as the vibration are not able to produce as sound is not able to reach to middle ear, but Navy researchers have discovered that sound under water is heard by the bone present behind the ear, vibrations mastoid.

Answer:

Transverse wave

Explanation:

Its because in transverse wave the particle displacement is perpendicular to the direction of wave propagation..hope it helps you...

The answer is 65.3 inches tall

Explanation:

To know the heigh of Sammy in inches it is necessary to convert the 5 feet to inches and add this number to 5.3 inches as the statement mentions "Sammy is 5 feet and 5.3 inches tall". Additionally, it is known each foot is equal to 12 inches ( 1 foot = 12 inches). According to this, the simplest method to convert feet to inches is to multiply the feet given by 12. The process is shown below:

1 foot  = 12 inches

feet to inches =  number of feet x 12

5 feet x 12 = 60 inches

This means 5 feet is equal to 60 inches. Now, 60 inches + 5.3 inches = 65.3 inches (total height of Sammy in inches)

Answer:

Explanation:

Take note that when the fuel of the rocket is consumed, the acceleration would be zero. However, at this phase the rocket would still be moving up until all the forces of gravity would dominate and change the direction of the rocket. Hence, there will be a need to calculate two distances, one from the ground until the point where the fuel is consumed and from that point to the point where the gravity would change the direction.

Given:

a = 76.8 m/s^2

t = 1.99 s

Solution:

d = vi (t) + 0.5 (a) (t^2)

d = (0) (1.99) + 0.5 (76.8) (1.99)^2

d = 0+38.4×3.9601

d = 152.068m

vf = vi + at

vf = 0 + 76.8 (1.99)

vf = 152.83 m/s (velocity when the fuel is consumed completely)

Then, we calculate the time it takes until it reaches the maximum height.

vf = vi + at

0 = 152.83+(-9.8) (t)

0 = 152.83 + (-9.8) (t)

-152.83 = -9.8t

t = 152.83/9.8 s

t = 15.59s

Then, the second distance

d= vi (t) + 0.5 (a) (t^2)

d = 152.83 (15.59) + 0.5 (-9.8) (15.59^2)

d = 2382.6197- 1190.93

d = 1191.68m

Then, we determine the maximum altitude:

d1 + d2 = 152.068 m + 1191.68m = 1343.748m

Answer:

degrees

Explanation:

If a direction is somewhere between north and east, it is measured in degrees.

This measurement will be possible thanks to the existence of geographical coordinates that are some 'imaginary lines' that help us find our location on the earth's surface. These lines are called latitude and longitude, both of which are measured in degrees.

It is like a sea battle game where you have to combine the rows and columns in order to identify where the targets are located. Geographic coordinates work the same way, you must combine the rows and columns of the planisphere to identify the locations of the planet. So the lines would be the latitudes and the columns the longitudes.

Answer:

x = 27.3 m

Explanation:

This is a projectile launching exercise, let's start by looking for the time it takes for the rock to reach the height of the window.

Let's use trigonometry to find the velocities of the rock

           sin 40 = [tex]v_{oy}[/tex] / v

           cos 40 = v₀ₓ / v

           v_{oy}= v sin 40

           v₀ₓ = v cos 40

           v_{oy} = 30 sin 40 = 19.28 m / s

           v₀ₓ = v cos 40

           v₀ₓ = 30 cos 40 = 22.98 m / s

we look for the time

        [tex]v_{y}^2[/tex] = v_{oy}^2 - 2 g y

         v_{y}^2 = 19.28 2 - 2 9.8 16 = 371.71 - 313.6 = 58.118

        v_{y} = 7.623 m / s

we calculate the time

          v_{y} = v_{oy} - gt

          t = (v_{oy} - v_{y}) / g

          t = (19.28 -7.623) / 9.8

          t = 1,189 s

since the time is the same for both movements let's use this time to find the horizontal distance

           x = v₀ₓ t

           x = 22.98 1,189

           x = 27.3 m

Answer:

Explanation:

Given the following :

Temperature (Th) of hot reservoir = 30°C (30 +273) = 303K

Temperature (Tc) of cold reservoir = 0°C (273K)

Quantity (Q) of heat transferred from hot reservoir = 400 J

Total change in entropy (ΔStotal) :

ΔStotal = ΔShot + ΔScold

ΔS = Q/T

Hot reservoir is losing 400J of heat ;

Q = - 400 J

ΔShot = Q/Th

ΔShot = - 400/303

ΔShot = - 1.32 J/K

ΔScold = Q/T

ΔScold = 400 / 273

ΔScold = 1.47 J/K

ΔStotal = ΔShot + ΔScold

ΔStotal = - 1.32 + 1.47

ΔS total = 0.15 J/K

Answer:

-400/303 = -1.32

400/273 = 1.47

-1.32 + 1.47 =

.15 J/K

Explanation:

a p e x

Answer:

The retina comprises of rod and cone cells . The rod cells are responsible for black and white vision and require low light levels while the cone cells are responsible for color vision and require good/high light levels for better functioning.

When faint stars are looked at on the edges of the vision it allows more light from faint objects to strike the rod cells which then becomes more visible.

Answer:

Take up space

Explanation:

Actually we know this by the definition of matter which states that "matter is any substance that has mass and takes up space by having volume."

hope it helped you:)

Answer: Efficiency signifies a peak level of performance that uses the least amount of inputs to achieve the highest amount of output.

Explanation: It minimizes the waste of resources such as physical materials, energy, and time while accomplishing the desired output.

Answer:

The efficiency of a simple machine is defined as the ratio of useful work done by the machine ( output work) to the total work out into the machine ( input work).

Explanation:

If a machine overcomes a load ' L ' and the distance travelled by the load is 'Ld' , the work done by the load is L× LD. It is also called output work or useful work.

Therefore, [tex] \boxed{Output \: work \: = L \: \times \: Ld}[/tex]

Likewise, The effort applied to overcome the load is 'E' and the distance covered by effort is 'Ed' , the work done by effort is E × Ed. It is also called input work.

Therefore, [tex] \boxed{Input \: work = E \times Ed}[/tex]

The efficiency of a simple machine is defined as the ratio of output work to the input work .

Therefore, [tex] \boxed{Efficiency ( η)= \frac{outpt \: work}{input \: work} \times 100\%}[/tex]

Efficiency is expressed in percentage. It is a ratio of two works. A machine is never 100% efficient. It is because no machine is friction free and due to friction, some of the input energy is wastes in the form of heat energy.

[tex] \mathrm{Hope \: I \: helped!}[/tex]

[tex] \mathrm{Best \: regards!}[/tex]

Answer:

  357.5 miles

Explanation:

  distance = speed × time

  distance = (55 mi/h) × 6.5 h = 357.5 mi

The train will travel 357.5 miles in 6.5 hours.

Answer:

the car uses teleportation, to zip to one side of the photo, to the other

Explanation:

Answer:

1) The balloon will shrink

2) The balloon will grow bigger and regain its shape

Explanation:

By the kinetic theory of gases, we have;

[tex]v_{rms} = \sqrt{\dfrac{3 \cdot R \cdot T}{MW} }[/tex]

[tex]P = \dfrac{n \cdot MW \cdot vrms^2}{3 \cdot V}[/tex]

Where;

[tex]v_{rms}[/tex] = RMS Speed

R = The universal gas constant

T = The temperature

MW = The Molecular weight

n = The number of moles

V = The volume

P = The pressure

1) When the balloon is placed in the refrigerator for  minutes, the temperature inside the balloon will drop and RMS speed will reduce, however due to the elastic wall of the balloon, the pressure will remain the same therefore the volume  will reduce and the balloon will shrink

2) When the balloon is placed on the kitchen counter, the temperature inside the balloon will rise leading to the increase in the RMS speed which will raise the pressure effect on the wall  of the balloon as the balloon is made of elastic material, as the pressure rises, the wall expands to keep the pressure constant and the volume occupied by the air particles will increase, the balloon will grow bigger and regain its shape.

Answer:

40 ms¯².

Explanation:

To solve this problem, we shall illustrate the question with a diagram.

The attached photo gives a better understanding of the question.

From the attached photo:

Velocity (v) = 160 ms¯¹

Time (t) = 4 secs.

Acceleration (a) =?

Acceleration (a) = Velocity (v) /time (t)

a = v/t

a = 160/4

a = 40 ms¯²

Therefore, the initial acceleration of the rocket is 40 ms¯².

Answer:

If I understand correctly. Line B is parallel to the circle. Also, the angle is less than 90.

'Circle' is characterized as "a two-dimensional geometric figure comprising of the set of all those points in a plane that are at equal distance from the center."

1). Line B would be considered as the 'tangent' in association with the given circle.

2). The angle lying among the lines A and B would be of 90° i.e. right angle.

Given that,

A circle with line A drawn through its center

Line B moves while touching the edge of the circle and intersects line A outside the circle.

Learn more about 'circle' here:

brainly.com/question/11833983

Explanation:

Average speed = distance / time

v_avg = 47 km / 1.72 hr

v_avg = 27.3 km/hr

Answer:

Hey there!

Mixtures are physically combined and can be separated. For example, sand and water is a mixture.

Pure substances are samples of matter with definite, and unchangeable chemical properties. For example, diamond is a pure substance.

Let me know if this helps :)

a pure substance is a substance that has not been mixed with anything, a mixture has been mixed with another substance. an example is

dirt +water=mud iron is an example of a substance

Answer:

9 kg

Explanation:

Momentum is mass times velocity.

p = mv

36 kgm/s = m (4 m/s)

m = 9 kg

The mass of the bicycle is 9 kg.

The momentum of the bicycle is the product of mass and velocity of the bicycle.

P = mv

where;

m = P/v

m = 36/4

m = 9 kg

Thus, the mass of the bicycle is 9 kg.

Learn more about momentum here: https://brainly.com/question/7538238

Answer:

[tex]r = \frac{v}{i} = v = ri \\ i = \frac{v}{r} [/tex]

Answer:

This is called restricted speed

Answer:

I should be active for 15 hours to meet the physical activity requirement.

Explanation:

Since time dilates in moving objects, we use the formula t = t₀/√(1 - β²) where t = time in space vehicle, t₀ = time on earth = 9 hours and β = v/c where v = speed of space vehicle = 0.8c.

So, t = t₀/√(1 - β²)

t = 9/√(1 - (v/c)²)

= 9/√(1 - (0.8c/c)²)

= 9/√(1 - (0.8)²)

= 9/√(1 - (0.64)

= 9/√0.36

= 9/0.6

= 15 hr

So, according to a timer on the space vehicle, I should be active for 15 hours to meet the physical activity requirement.

Answer:

1.) Sowing

2.) Respiration

3.) Soil preparation or cultivation or ploughing

4.) Fertility

5.) 2, 4 -D

6.) winnowing threshers

7.) Surface irrigation and sprinkler irrigation

8.) Weeds

9.) Transplantation

10.) Aeration

Explanation:

1.) Seed drill sows crop seed

2.) Ploughing assist in the respiration and penetration of the roots of a growing plants

3.) Tilling the soil is breaking of the soil lumps and turning of the soil

4.) Manure and fertilizers supply nutrient to the soil for the uptake by plant in food production

5.) 2, 4 -D are a range of weedicide containing 2,4-D as the active ingredient

6.) Winnowing is the separation of grain from straw

Threshers remove seeds from husks and stalks

7.) Surface irrigation -gravity enables the flow of the water

and sprinkler irrigation- Use of preset tools for irrigation

8.) Weeds are the unwanted, in situ, growing plants close to the crops

9.) Transplantation is the method of relocating plants

10.) Excess water limits access of the roots and seeds to atmospheric oxygen

The answer is:

-5846.75

Answer:

His conclusion best illustrates a pessimistic outlook.

Explanation:

As seen in the question above, Ken got 20% of his final grade in the first test he did for this class, that is, there will be other tests that can provide him to reach the grade needed to pass the class. However, even if there are possibilities, he believes that he will not pass the class, he does not have a positive and optimistic view of his future in this class and is sure that he will fail. This negative view of the future is an example of a pessimistic outlook.

Answer:

External locus of control

Explanation:

External locus of control is an attitude people possess that makes them attribute their failures or successes to factors other than themselves. The opposite of this type of attitude is the Internal locus of control where the individuals take responsibility for the outcomes of their actions whether good or bad. One good thing about the external locus of control is that when the individuals with this characteristic record successes, they attribute it to others and this presents them as people with team spirit. However, when they record failures, they do not want to take the blame, but rather attribute it to others.

Fred exhibits an external locus of control because he attributed his speeding to other factors like the road signs and GPS instead of fully admitting that it was his fault.

Answer:

There will  be a huge problem of holding the wire strands together, and the power losses will also be amplified.

Explanation:

The force per unit length on two current carrying conductors, lying parallel to each other is proportional to the product of the current through the conductors, and inversely proportional to their distance apart. This force is attractive if the current flows through these conductors in the same direction, and is repulsive if it flows in the opposite direction.

For the strand of wire that make up a high voltage wire bundle, there will be a force of attraction pulling the wires closer to each other, and they will experience the maximum pulling force possible, since they lie next to each other. This force helps to hold these wires in a high tension wire strand together, limiting the area, and reducing "skin effect."

In the case that this wires in the wire strand acts in opposite of the known behavior, the wires will repel and push each other apart. This pushing apart will increase power loss due "skin effect" which is increased by an increase in exposed surface area of the wire strands. This will pose a big problem for high tension transmission.