Questions posted in Physics

What energy transfers happen when you cook sausages on a camp fire burning wood?

Heat energy, because of the fire burning the wood and the sausages.

ANSWERED AT 06/12/2019 - 04:24 PM


QUESTION POSTED AT 06/12/2019 - 04:24 PM

What is the momentum of an object at rest, in m/s?


Momentum = (mass) x (speed)

If the speed is zero, then the momentum is zero.

ANSWERED AT 06/12/2019 - 04:17 PM


QUESTION POSTED AT 06/12/2019 - 04:17 PM

How much force is required to accelerate a 2 kg mass at 3 m/s2


Force = (mass) x (acceleration)                  Newton's second law of motion.

Force = (2 kg) x (3 m/s²)  =  6 newtons.

ANSWERED AT 06/12/2019 - 04:08 PM


QUESTION POSTED AT 06/12/2019 - 04:08 PM

Dark spots on the photosphere are known as A. the corona. B. the chromosphere. C. sunspots. D. solar wind.

The dark spots that are found on the photosphere are called sunspots. These are a temporary phenomena and are areas of different temperature compared to the surroundings. Sunspots are at a lower temperature compared to the surrpundings and they are created due to magnetic field flux. They can stay on from a few days to a few months and eventually decay.

ANSWERED AT 06/12/2019 - 04:05 PM


QUESTION POSTED AT 06/12/2019 - 04:05 PM

Which element makes up earth's atmosphere? a. hydrogen b. carbon c. oxygen d. nitrogen

The answer is D.nitrogen. the atmosphere is mostly made up of nitrogen.(95% is nitrogen) and (2% oxygen) and and (3% of other gases)

ANSWERED AT 06/12/2019 - 04:05 PM


QUESTION POSTED AT 06/12/2019 - 04:05 PM

A dolphin swims 1.85 km/h. How far has the dolphin traveled after .60 h?

1.85 km every hour x 0.60 hours

1.85 x 0.6 = 1.11


The dolphin traveled 1.11 km.

ANSWERED AT 06/12/2019 - 04:02 PM


QUESTION POSTED AT 06/12/2019 - 04:02 PM

How many resistors are found in this circuit? A) 0 B) 1 C) 2 D) 3

Answer: option C.

Explanation:

As the current flows along the circuit, the resistors make a "resistance" which lowers the intensity of the current in the circuit.

The resistors in a circuit are represented with some sharp pikes, and here you can see that you have 3 of those in this circuit.

One is alone, and the other two are in a separated segment, which is called resistors and can be approximated to one resistor.

If the resistances of the resistors are R1, R2, and R3, where R1 and R2 are the resistors in parallel, we can use the approximation:

Ra = (R1*R2)/(R1 + R2)

You may do this when you want a resistor with high resistance, but the resistors that you have don't have a resistance high enough, you can put them in this way and create a stronger resistor.

So now we have the resistances Ra and R3.

In this viewpoint, we only have 2 resistors in the circuit.

ANSWERED AT 06/12/2019 - 04:00 PM


QUESTION POSTED AT 06/12/2019 - 04:00 PM

The dark, smooth surface areas of the Moon are known as A. craters. B. rilles. C. maria. D. highlands.

The dark, smooth surface areas of the Moon are known as C. maria. Although they are a type of craters, they are not called that way, but rather their name is maria, because scientists who first researched this areas thought they were seas or oceans. In Latin, the word for sea is mare, and plural is maria, which is why these areas are also called that way because they resemble these waters.

ANSWERED AT 06/12/2019 - 03:58 PM


QUESTION POSTED AT 06/12/2019 - 03:58 PM

The cost, density and resistivity of copper, steel and aluminum

Density of copper: 8,9
Density of steel: 7,7
Density of aluminum: 2,7
And
Resistivity of copper: 1,7
Resistivity of steel: 16,9
Resistivity of aluminum: 2,7

Hope I Helped You!!! :-)

Have A Good Day!!!

ANSWERED AT 06/12/2019 - 03:56 PM


QUESTION POSTED AT 06/12/2019 - 03:56 PM

A constellation is _______ that forms a pattern resembling animals, mythological characters, or objects. A. a group of meteors B. a group of stars C. an entire galaxy D. one single planet

The answer is the option B. a a group of stars. So the complete sentence is "A constellation is a group of stars that forms a pattern resembling animals, mythological characters, or objects. Most names of constellations originated in ancient times and took their names from the patterns that observer could watch in the sky. Some examples of constellations are Orion, Aquarium, Cancer, etc.

ANSWERED AT 06/12/2019 - 03:54 PM


QUESTION POSTED AT 06/12/2019 - 03:54 PM

What is the mass of a car that has a speed of 30 m/s and a momentum of 45,000 kg, m/s


                                                   Momentum = (mass) x (speed)

Divide each side by (speed):      Mass = (momentum) / speed

                                                   Mass = (45,000 kg-m/s) / (30 m/s) =

                                                                   1,500 kg .

ANSWERED AT 06/12/2019 - 03:43 PM


QUESTION POSTED AT 06/12/2019 - 03:43 PM

If a 2,300 kg car is accelerating at 16 m/s^2, what is the force it is producing?


Force = (mass) x (acceleration)

In order to accelerate the car at that rate, a force of

                  (2,300 kg) x (16 m/s²) = 36,800 newtons
                                               (about  8,270 pounds ... 4.14 tons !)

has to be coming from somewhere ... presumably from the straining,
screaming, smoking engine under the hood.

The force it might apply to an object it runs into will depend on the
shape and composition of that object.

ANSWERED AT 06/12/2019 - 03:37 PM


QUESTION POSTED AT 06/12/2019 - 03:37 PM

Explain why a high speed collision between two cars would cause more damage than a low speed collision between the same two cars?

I've would cause more damage, because there is nore momentum and input force equals output force and the momentum is transferred between the two cars more so than if they had a lower velocity

ANSWERED AT 06/12/2019 - 03:35 PM


QUESTION POSTED AT 06/12/2019 - 03:35 PM

Compare the outermost electrons of an atom with the inner most electrons of an atom in terms of energy

The innermost electron of an atom has the lowest level of energy while the outermost electron has the highest level of energy.
There are different energy levels in the atoms of elements, for an atom to go into an higher level it has to obtain more energy and to go to lower level it has to lose energy.

ANSWERED AT 06/12/2019 - 03:24 PM


QUESTION POSTED AT 06/12/2019 - 03:24 PM

What would you do to change the volume of gas?


The only way to do that is to reduce the
volume of the container the gas is in.

ANSWERED AT 06/12/2019 - 03:21 PM


QUESTION POSTED AT 06/12/2019 - 03:21 PM

Why do the two elements silver and iron have different properties

Because the atomic number is diffrent and I belive that they also have diffrent atomic masses

ANSWERED AT 06/12/2019 - 03:21 PM


QUESTION POSTED AT 06/12/2019 - 03:21 PM

Explain how if two cases are side by side on a shelf one an have more potential energy


Potential energy = (mass) x (gravity) x (height).

Even if the two objects are at the same height, the one
with more mass has more potential energy.

ANSWERED AT 06/12/2019 - 03:20 PM


QUESTION POSTED AT 06/12/2019 - 03:20 PM

Fusion occurs in the _______ of the Sun, where the pressure and temperature are very high.


Nuclear fusion occurs in the CORE of every star, where
the pressure and temperature are very high. 

If fusion does not take place in the core, then you don't have a star.

ANSWERED AT 06/12/2019 - 03:16 PM


QUESTION POSTED AT 06/12/2019 - 03:16 PM

Do you get the same answer if you drive 1.0x10²km at each of the two speeds


That all depends on what the question is.

If the question is "How long does it take you to get there ?",
then the answer is 'No' .

If the question is "What color is the car ?", then
the answer is 'Yes' .

ANSWERED AT 06/12/2019 - 03:15 PM


QUESTION POSTED AT 06/12/2019 - 03:15 PM

If a solid is 180g what is the density


If a lump of something has  180g  of mass,
then its density is

                 (180g) / (its volume in cm³) .

ANSWERED AT 06/12/2019 - 03:13 PM


QUESTION POSTED AT 06/12/2019 - 03:13 PM

A substance can be classified by its physical properties which are properties that

Physical properties are properties that you can see, feel and measure, they do not change the matter of the substance. Some examples of physical properties are Mass, Color, Shape, Hardness and Boiling point.



ANSWERED AT 06/12/2019 - 03:05 PM


QUESTION POSTED AT 06/12/2019 - 03:05 PM

How much time would it take for an airplane to reach its destination. If it traveled at an average velocity of 790km/hr east for a distance of 4,700 kilometres

It would be 5.94 hours but you can round it to just 6 hours.

ANSWERED AT 06/12/2019 - 03:01 PM


QUESTION POSTED AT 06/12/2019 - 03:01 PM

What evidence did Alfred Wegener use to support his theory of continental drift?

Explanation:

Alfred Wegener was a meteorologist and geologist. He was inspired by a map of continents to start the journey of explaining Earth's geological history. He gave the theory of continental drift which says that the continents of Earth have moved relative to each other over time. He used following evidences to support his theory:

1. The facing side of South America's and Africa's shoreline interlocks perfectly. Which implies they must have been joined together in history.

2. Fossil of same type of reptiles found on different continents separated by huge oceans.

3. Matching the rock pieces on either side of the Atlantic oceans.

ANSWERED AT 06/12/2019 - 02:56 PM


QUESTION POSTED AT 06/12/2019 - 02:56 PM

A 20 kg crate of books is at rest on a table. what is the normal force on the books?


The weight of 20 kg is

                             (mass) x (gravity) =

                                   (20 x 9.8) = 196 newtons, downward.

There must be a force of 196 newtons upward on the mass. 
Otherwise the mass is accelerating either up or down.
 

ANSWERED AT 06/12/2019 - 02:54 PM


QUESTION POSTED AT 06/12/2019 - 02:54 PM

Greyhounds can accelerate at 7 m/s2 at the start of a race. How much force does it take a 35 kg dog to produce this acceleration


Force = (mass) x (acceleration)              Newton's second law of motion.

Force = (35 kg) x (7 m/s²)  =  245 newtons

                                    (about  55 pounds)

ANSWERED AT 06/12/2019 - 02:54 PM


QUESTION POSTED AT 06/12/2019 - 02:54 PM

Which phrase describes an atom?


You haven't included the list of choices that goes with the question, so it's
impossible for me to choose the correct one, or to help you choose it.

Regarding my ability to answer the question and collect the 5-point bounty,
I'm free to make up any phrase of my own that correctly describes an atom.

-- very very very very very very very tiny

-- includes even tinier particles, with electric charges
   both positive and negative

-- smaller than the wavelength of visible light

ANSWERED AT 06/12/2019 - 02:45 PM


QUESTION POSTED AT 06/12/2019 - 02:45 PM

If you wanted to detect x-rays coming from the sun, where would you place the detector? And why?

The Sun does emit xrays. You'd have to place your sensor above the Earth's atmosphere because it blocks out nearly all x-rays. This is why we have the Chandra observatory ( http://chandra.harvard.edu/xray_astro/absorption.html )

ANSWERED AT 06/12/2019 - 02:45 PM


QUESTION POSTED AT 06/12/2019 - 02:45 PM

A bus slams on its breaks and goes from 30 km/hr to 15km/hr in 4 seconds. What is its acceleration?


Acceleration = (change in speed) / (time for the change).

Change in speed = (15 - 30) = -15 km/hr
Time for the change = 4 sec

Acceleration = (-15 km/hr) / (4 sec) = -3.75 km/hr per second .

Is that a lot ?  Not much ?

Let's convert it to a unit that we can think about:

     (-15 km/hr) x (1,000 m/km) x (1 hr / 3,600 sec) =

           (-15 x 1,000) / (3,600)  =  -(4 and 1/6) m/sec .

So the acceleration of the bus is    -(4 and 1/6) m/sec² .

The negative sign means that it slowed down.

(4 and 1/6) m/sec²  is about  42%  of the acceleration of gravity ...
the acceleration the bus would have if it drove off of a cliff.

When the car or the bus you're riding in slows down at that rate,
you feel  42%  of your weight pulling you forward against your
seat belt.  That's quite a drastic acceleration !

ANSWERED AT 06/12/2019 - 02:36 PM


QUESTION POSTED AT 06/12/2019 - 02:36 PM

Every 4 years we have a leap year on our calander to make up the extra.......


The Earth takes very nearly (365 and 1/4) days to go around the sun.

If our calendar always had 365 days, then the year would end and re-start
too soon, and the beginning of Spring (and every other season) would
eventually drift into the months after March.

If our calendar always had 366 days, then the year would end and re-start
too late, and the beginning of Spring (and every other season) would
eventually drift into the months before March.

We can't make calendars with an extra quarter-day in each year.  But we
keep them lined up with the real year by saving up the quarters, and adding
one full day to the calendar every 4 years.

ANSWERED AT 06/12/2019 - 02:35 PM


QUESTION POSTED AT 06/12/2019 - 02:35 PM