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

Answer:

Confusion

question:
is it multiple choice? or you have to write it

Answer:

Using

1/2mv^2 = work done by friction

work done = force x distance

lets call the force 3 N

lets call v = 3 m/s

lets call mass = 2 kg

0.5 x 2 x 3^2 = 9 J

9/3N = 3 m/s

now times 3 m/s by square root of 2 of which is 1.4142

3 x 1.4142= 4.2426 m/s

0.5 x 2 x 4.2426^2 = 18

18/2N = 9 m

Answer: "Surface tension is a film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area."

Hope this helps!

Answer:

Explanation:

Surface tension is the property of a liquid surface. It is an effect where the surface of the liquid is strong.

example - small insects can walk on water as they do not have enough weight to penetrate it.

This image might help you

Hope it helps

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Answer:

Parallel processing

Explanation:

It is a parallel processing because it involves the brain processing many part of problem simultaneously.

The brain natural mode of information involves performing many task .

It is also ability of the brain to simultaneously process incoming stimuli or signals of different quality. It is a part of brain's vision and divide what is seen into four major parts which are color, motion, shape, and depth.

Answer: B)  Parallel processing

Answer:

1st question c part

2nd question c part

tape measure?

Hope that helped!!! k

instrument is used to measure is Tape measure

Answer:Testing

Explanation:Once a scientist has made a hypothesis, what would they typically do TESTING nextn

Once a scientist has made a hypothesis, they would typically do testing, therefore the correct answer is option B

Scientific claims are statements made in science based on an experiment.

These Scientific claims are backed by the experimental data and their true results obtained from scientific investigation and experimentation.

When a scientist performs a fair test is one in which all other circumstances are maintained while just one variable is changed at a time.

Scientists frequently discover that their hypotheses and predictions were not supported by the results of their experiments. In these situations, they will communicate the findings of their experiment before revising their original hypotheses and predictions in light of the new knowledge they have gained.

The right response is option B because once a scientist has made a theory, they usually do testing.

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Answer:

Explanation:

On rubbing a glass rod with silk, the electrons from the glass rod get transferred to the silk. The silk now has an excess of electrons and so is negatively-charged. On the other hand, the glass rod is deficient in electrons and hence is positively-charged.

In the above case, the silk undergoes negative electrification.

Now, when the positively charged glass rod is touched on the disc of a negatively charged gold leaf electroscope, the electrons shifts towards rod, hence amount of charge on gold leaves decreases and the divergence between the gold leaves decreases as unlike charges attract each other.

Hence, the divergence decreases when a glass rod rubbed with silk is brought near the disc of negatively charged electroscope.

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Answer:

Distance covered 28 km

displacement is 22.8 km North-East

Explanation:

Distance shows how far apart objects or points are from each other. The distance he covered is the sum of all the distance travelled. Therefore:

Distance covered = 12 km + 6 km + 10 km = 28 km

Displacement is a vector quantity (has direction). It is the overall change in position.

The total distance traveled north = 12 km + 10 km = 22 km

The distance traveled east = 6 km

The displacement (d) is:

d² = 22² + 6² = 484 + 36

d² = 520

d = √520 = 22.8 km

Therefore the displacement is 22.8 km North-East

Distance covered 28 km

displacement is 22.8 km North-East

Distance covered

= 12 km + 6 km + 10 km

= 28 km

Now

The total distance traveled north = 12 km + 10 km = 22 km

And,  

The distance traveled east = 6 km

So,  

The displacement (d) is:

[tex]d^2 = 22^2 + 6^2\\\\ d^2 = 520\\\\d = \sqrt520[/tex]

= 22.8 km

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Explanation:

meter=100cm

cm=10^-2 m

min=60 sec

0.0141666667 m / s

The conversion of 85 cm/min would be 0.0133 m/s

The total displacement covered by any object per unit of time is known as velocity. It depends on the magnitude as well as the direction of the moving object.

As given in the problem position-time graph of an object.

As we know that slope of the position time curve represents the velocity of the object

As given in the problem we have to convert 85 cm/min to m/s.

Let us first convert the displacement in cm to meters

100 cm = 1 m

1 cm = 1/100 m

85 cm = 85×1/100 m

          = 0.85 m

similarly, convert time given in minutes to the seconds

1 min = 60 s

velocity = displacement /time

velocity  =  0.85 / 60 m/s

             =0.01333 m/s

Thus, we converted  85 cm/m into 0.0133 m/s

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Answer:

Acceleration = 0.1464 m/s^2

Explanation:

From the question, the parameters given are:

Mass m = 1000 kg

The driver and a help pulled it with two ropes respectively with forces 200√2 N 45° east of south and 400N 30° north of east

Find the resultant force along the x axis.

(400 × cos30) - (200√2 × cos45)

346.4 - 200 = 146.4 N

therefore, the resultant force = 146.4N

The formula to use for the acceleration of the car is

F = ma

Where

F = resultant force

M = mass of the car

a = acceleration of the car

Substitute f and m into the formula

146.4 = 1000 × a

Make a the subject of formula

a = 146.4 / 1000

a = 0.1464 m/s^2

Therefore, the car accelerate at 0.1464 m/s^2

Answer:

1.7 BTU

Explanation:

q = mCΔT

q = (25 g) (0.9 J/g/°C) (100°C − 20°C)

q = 1800 J

q = 1800 J × (1 BTU / 1055 J)

q = 1.7 BTU

This question is incomplete; here is the complete question:

Marco is conducting an experiment. He knows the wave that he is working with has a wavelength of 32.4 cm. If he measures the frequency as 3 hertz, which statement about the wave is accurate?

A. The wave has traveled 32.4 cm in 3 seconds.

B. The wave has traveled 32.4 cm in 9 seconds.

C. The wave has traveled 97.2 cm in 3 seconds.

D. The wave has traveled 97.2 cm in 1 second.

The answer to this question is D. The wave has traveled 97.2 cm in 1 second.

Explanation:

The frequency of a wave, which is in this case 3 hertz, represents the number of waves that go through a point during 1 second. According to this, if the frequency of the wave is 3 hertz this means in 1 second there were 3 waves. Moreover, if you multiply the wavelength (32.4cm) by the frequency (3) you will know the distance the wave traveled in 1 second: 32.4 x 3 =  97.2 cm. This makes option D the correct one as the distance in 1 second was 97.2 cm.

Answer:Is D!

Explanation:TEAT(Sorry) -_-*

Answer:

The collapse of a protostar with less than 0.08 times the mass of the Sun is halted by DEGENERACY PRESSURE. b. As a protostar shrinks in size, its central temperature rises along with its THERMAL PRESSURE. c. A star that has not yet finished forming is called a__PROTOSTAR_____. d. A forming star spins more rapidly as it collapses because of conservation of ANGULAR MOMENTUM. e. If a protostar has a mass too small for it to sustain nuclear fusion it becomes the type of object known as a____BROWN DWARF____

Answer:

[tex]\boxed{\mathrm{view \ explanation}}[/tex]

Explanation:

Energy is the capacity of an object to do work. Energy must be transferred to an object in order to do work. The SI unit of energy is Joules (J).

Answer:

See below

Explanation:

Energy is the "capacity/ability to do work". If the body has the ability to do work, we mean that the body possesses energy.

Units:

Energy is measured in Joules (J)

Types:

The two "main" types of energy are:

1) Kinetic Energy

2) Potential Energy

Answer:

0 m/s

Explanation:

Average velocity is displacement over time.

v_avg = Δx / Δt

Displacement is the distance between the start and the finish.

The circumference of the track is:

C = 2πr

C = 2π (7 m)

C ≈ 44 m

The distance covered by the object is:

d = vt

d = (11 m/s) (8 s)

d = 88 m

So the object travels 2 circumferences, meaning it ends back where it started.  Therefore, the displacement is 0 m, and the average velocity is 0 m/s.

Answer:

Explanation:

Average rate = gallons / minutes

If 12.5gallons in 5mins

Xgallons in 1mins

12.5/5 = 2.5gallons per minute

Answer:

(a) 0.42 m/s²

(b) 83 N

Explanation:

Assuming g = 10 m/s².

Draw free body diagrams for the child and the chair.

There are three forces on the child:

Tension force T pulling up,

Weight force Mg pulling down,

and normal force N pushing up.

There are three forces on the chair:

Tension force T pulling up,

Weight force mg pulling down,

and normal force N pushing down.

Sum of forces on the child in the y direction:

∑F = ma

T + N − Mg = Ma

Sum of forces on the chair in the y direction:

∑F = ma

T − N − mg = ma

Add the equations together to find the acceleration.

2T − Mg − mg = Ma + ma

a = (2T − Mg − mg) / (M + m)

a = g (2T − Mg − mg) / (Mg + mg)

a = (10 m/s²) (2 × 250 N − 320 N − 160 N) / (320 N + 160 N)

a = 0.42 m/s²

Plug into either equation to find the normal force.

T + N − Mg = Ma

250 N + N − 320 N = (320 N / 10 m/s²) (0.42 m/s²)

N = 83 N

Answer: 7 km

Explanation: 12 minutes is 1/5 of an hour. 35/5=7

Answer:

the force constant  k = 2.369 N/m

Explanation:

Given that:

A type of cuckoo clock keeps time by having a mass bouncing on a spring, usually something cute like a cherub in a chair.

with period T = 0.500 s and a mass of 0.0150 kg, Then the force constant can be calculated by using the formula:

[tex]\mathtt{T = 2 \pi \ \sqrt{\dfrac{m}{k} }}[/tex]

where;

T = time period

m = mass

k = force constant.

By making k the subject of the formula; we have:

[tex]\mathtt{T^2 = 4 \pi^2 (\dfrac{m}{k})}[/tex]

[tex]\mathtt{k =\dfrac{4 \pi ^2 \ m}{T^2}}[/tex]

replacing our given values , we have:

[tex]\mathtt{k =\dfrac{4 (3.142) ^2 \ \times 0.0150 }{0.5^2}}[/tex]

[tex]\mathtt{k =\dfrac{39.49 \ \times 0.0150 }{0.25}}[/tex]

[tex]\mathtt{k =\dfrac{0.59235 }{0.25}}[/tex]

k = 2.369 N/m

According to the information available in the question, the force constant is 2.37N/m.

Using the relation;

T = 2π√m/k

T = period = 0.500 s

m = mass in kilograms = 0.0150-kg

k = spring constant = ?

Making k the subject of the formula;

k = 4π^2m/T^2

k = 4 × (3.142)^2 ×  0.0150/(0.500 )^2

k = 2.37N/m

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Answer:

Water waves are an example of waves that involve a combination of both longitudinal and transverse motions. As a wave travels through the waver, the particles travel in clockwise circles. The radius of the circles decreases as the depth into the water increases.

Answer:

Regardless of how the steps are documented, the goal of scientific method is to gather data that will validate or invalidate a cause and effect relationship.

Hope this helped!!!

Explanation:

Distance = speed × time

d = (55 mi/hr) (6.5 hr)

d = 357.5 mi

Answer:

In this case reflection occurs.

Explanation:

This happens when they bounce on objects that they can not pass through.

Hope it helps

okay.

Answer:

a. Walking burns up more energy.

b. 1740 kJ

c. This is because more intense exercise releases a lot of energy in a short period of time, whereas, less intense energy releases it energy gradually over a long period of time.

Explanation:

a. We know energy W = Pt where P = power and t = time.

Now for walking, t = d/v where d = distance = 5.00 km and v = speed = 3.00 km/hr and P = 290 W

So, t = d/v = 5.00 km/3.00 km/hr = 5/3 hr = 5/3 × 3600 s = 6000 s

W = Pt = 290 W × 6000 s = 1740000 = 1740 kJ

Now for running, t = d/v where d = distance = 5.00 km and v = speed = 10.00 km/hr

So, t = d/v = 5.00 km/10.00 km/hr = 0.5 hr = 0.5 × 3600 s = 1800 s and P = 700 W

W = Pt = 700 W × 1800 s = 1260000 = 1260 kJ

Since walking burns up 1740 kJ and running burns up 1260 kJ, walking burns up more energy.

b. It burns up 1740 kJ

c. This is because more intense exercise releases a lot of energy in a short period of time, whereas, less intense energy releases it energy gradually over a long period of time.

Answer:

Explanation:

A concave mirror is a curved mirror that is coated outwards. The outer part of the mirror is always coated. The nature of image formed by an object placed in front of a concave mirror can be real or virtual depending on the distance of the object on the axis from the mirror. The only time the object produces a virtual image is when it is placed between the focus and the pole of the mirror. The virtual image formed is a "MAGNIFIED and upright image"

For a convex mirror, the inner part is always coated and the nature of the image formed by the object doesn't depend on the distance between the image and the mirror. No matter where the object is placed, the image formed will always be virtual, upright and DIMINISHED. This means that magnification is always less than 1.

For a plane mirror, the nature of the image produced by a plane mirror also virtual because it is always formed behind the mirror. The size of the image formed is always THE SAME as that of the object. This means that the magnification is always equal to 1.

a) In summary, the difference between virtual images produced by concave, plane, and convex mirrors is that virtual images produced by concave mirror are MAGNIFIED, virtual images produced by plane mirror are THE SAME SIZE as that of the object and virtual images produced by convex mirrors are always DIMINISHED.

b) Magnification is defined as the ratio of the image distance to the object distance. Mag = v/u

Note that object distances are always positive, hence it is only the image distance that can either be positive or negative which in turn affects the magnification causing it to be positive or negative.

Negative image distance shows that the image is virtual while positive image distance shows that the image is real.

A negative magnification therefore shows that the nature of the image is a virtual image.

Answer:

Explanation:

On a hot summer afternoon the tent made up of white fabric will be preferred because white colour is a bad absorber and good reflector of heat. Hence, it will be more convenient to stay under fabric tent made of white during this season because heat will be reflected which makes shade provided by such tent to be cool and enjoyable.

While the black fabric tent will be preferred during winter because black materials are good absorber of heat and are poor reflector.

Answer:

The hypothesis may or may not be true and needs to be tested. It might be the answer to the problem. Hence, it must be tested thoroughly. When these predictions are tested again and again in independent scientific experiments and gets verified, the hypothesis is converted into a scientific theory.

The correct answer is B. Measurable

Explanation:

The use of science to investigate a phenomenon implies using measurements and observations to better understand a phenomenon or test a hypothesis. Moreover, science focuses on natural phenomena that can be objectively studied through measurement instruments such as a thermometer, balance, hydrometer, etc.

In this context, for a phenomenon to be studied by science this needs to be measurable because the use of precise instruments as wells as numbers allow scientist to analyze and understand a phenomenon. Moreover, phenomena that depend on personal perspectives and cannot be measure is considered as non-scientific.

This question is incomplete because the options are missing; I found the complete question:

What is a potential psychological outcome of regularly playing sports? Select one of the options below as your answer:

a. restlessness

b. improved mood

c. depression

d. lack of energy

The answer to this question is B. Improved mood

Explanation:

Practicing a sport regularly has multiple positive effects including physical and psychological benefits. In the case of psychological effects, this includes an improved mood, this is because practicing a sport reduces stress significantly and it is often associated with positive emotions such as motivation, confidence, or pride. Moreover, interacting with others in group sports allow individuals to positively interact with others, which contributes to a better mood. Thus, one potential psychological outcome of playing sports is an improved mood.