A little help please?

Dora rolled a marble down a ramp and recorded the potential energy and kinetic energy of the marble at different positions on the ramp, as shown in the table.

(Look at Picture)

Which is the constant variable in this experiment?
A. Mass of marble
B. Kinetic energy of marble
C. Potential energy of marble
D. Height of marble from ground

That's the retina. (A)

If you think of your eye like a film camera, the retina is the film.

If you think of your eye like a digital camera, the retina is the CCD.

kinematic equation used, g=10m/s/s approx

(a) 39.6 m/s and 30.7 m/s

Explanation:

Use the formula for speed as a function of distance made in a uniformly decelerated motion:

[tex]v_s^2 = v_0^2 -2sa[/tex]

with v_s the instantaneous speed at distance s and v_0 the initial speed (right after the explosion). "a" is the acceleration due to friction force, with negative sign in front of that term reflecting the fact the friction force acts against the direction of the motion. The scene after the explosion implies the fragments have come to a halt with the respective distances shown in the figure, i.e., for each fragment:

[tex]0 = v_0^2 -2sa[/tex]

and the initial speed v_0 remains to be determined:

[tex]v_0=\sqrt{2sa}[/tex]

The deceleration "a" due to friction can be found using the information we are given: the mass of a fragment and the coefficient of dynamic friction of 0.4:

[tex]F_{friction} = \mu\cdot m\cdot g \implies a = \mu\cdot g = 0.4\cdot 9.8\frac{m}{s^2}=3.92\frac{m}{s^2}[/tex]

So the initial velocities just after the explosion, as implied by the distances of 200m (v01) and 120m (v02) are, respectively:

[tex]v_{01}=\sqrt{2\cdot200m\cdot 3.92\frac{m}{s^2}}=39.6\frac{m}{s}\\v_{02}=\sqrt{2\cdot120m\cdot 3.92\frac{m}{s^2}}=30.7\frac{m}{s}[/tex]

(b) The speed of the third fragment is 31.7 m/s

Explanation:

Use the law of conservation of the momentum. At the time of the explosion there were three fragments. For two of them we have determined the initial speed in (a). Now we know that the total momentum of the system (container) right before the fragments were set into motion was 0. The total of the moment vectors (magnitudes with their directions) should still be 0 right after the explosion. Given the angle between the paths of fragment 0.5kg and 1kg, the total vector of their momentum can be calculated

[tex]\overline{p}_{12} = m_1 \overline{v}_1 +m_2\overline{v}_2\\[/tex]

and from the conservation law we know that the momentum of the third piece must be

[tex]\overline{p}_3=-\overline{p}_{12}[/tex]

in particular, its magnitude will be same as the magnitude of the resultant vector, counteracting (at an angle 180 degrees from the resultant). This will eventually allow us to determine the speed of the third fragment. The magnitudes are:

[tex] |\overline{p}_{1}| = 0.5kg\cdot 39.6 \frac{m}{s} = 19.8 kg\frac{m}{s}\\|\overline{p}_{2}|=1.0kg\cdot 30.7\frac{m}{s}=30.7kg\frac{m}{s}[/tex]

and the resulting moment:

[tex] |\overline{p}_{12}| = \sqrt{|\overline{p}_1|^2+|\overline{p}_2|^2+2|\overline{p}_1||\overline{p}_2|\cos 40^\circ}=47.6 kg\frac{m}{s}=|\overline{p}_3|[/tex]

and so the speed of the third fragment is 

[tex]v_{03} = \frac{|\overline{p}_3|}{1.5kg}=\frac{47.6kg\frac{m}{s}}{1.5kg}=31.7\frac{m}{s}[/tex]

(c) The total kinetic energy is 1617 Joules

Explanation:

[tex]E_k = \frac{1}{2}\sum_{i=1}^3 m_i v_{0i}^2 = 0.5\cdot(0.5\cdot 39.6^2+1\cdot 30.7^2+1.5\cdot 31.7^2)kg\frac{m^2}{s^2}=1617.0J[/tex]

(d) The area will be proportional to the fourth power of the initial velocities.

Explanation:

Consider the area of a circle with radius equal to the distance a fragment traveled. We can choose a fragment with largest such distance or choose the average of the areas for each fragment, or another geometric measure, however, this choice won't affect the qualitative answer.

The distance of a fragment "i"  traveled as a function of the initial speed is

[tex]s_i = \frac{v_{0i}^2}{2a}[/tex]

The circular area is then

[tex]A_i = \pi(\frac{v_{0i}^2}{2a})^2\implies A_i \propto v_{0i}^4[/tex]

The area due to a fragment with initial velocity is proportional to the fourth power of that velocity. This can be generalized to all fragments by assuming a common factor amplifying the velocities. Such factor will also show up in the fourth power in the area formula above, justifying the answer: the effect of an amplification of the initial speed has a fourth-power effect on the area of spread. 

according to conservation of momentum , total sum of momentum of the objects taking part in a collision is same before and after the collision.

Total momentum before collision = Total momentum after the collision

when a cue ball moving at velocity 1.5 m/s hits a billiard ball , transfer of momentum takes place between the balls such that total sum of momentum of cue ball and billiard ball remain same before and after the collision.

hence we say that the momentum is conserved.

The refractive index of a medium is independent of (not related to) the angles of incidence or refraction.  It's just a property of the medium.  (D)

Answer:

In the diagram attached, we will be able to see that the total force [tex]F[/tex] acting on the book is zero, according to the First Newton law, which states that an object is in equilibrium is the total force exerted on it is zero:

[tex]F=F_{T}-W=0[/tex]     (1)

Which is the same as:

[tex]F_{T}=W[/tex]     (2)

Where  [tex]W[/tex] is the weight of the book, which is the product of the mass [tex]m[/tex] of the book and the gravity acceleration [tex]g[/tex]:

[tex]W=mg[/tex]     (3)

Being  [tex]m=1.0kg[/tex] and  [tex]9.8\frac{m}{s^{2}}[/tex], the weight of the book is:

[tex]W=(1.0kg)(9.8\frac{m}{s^{2}})[/tex]

[tex]W=9.8N[/tex]     (4)

Then, equation (2) means that the force [tex]W[/tex] due to the weight acting on the book is the same in magnitude but in opposite direction to the force [tex]F_{T}[/tex] the table exerts on the book, which is in accordance with the third Newton law of action and reaction.    

A. Illustrates how a theory becomes a law

Answer:

A. Illustrates how a theory becomes a law

Explanation:

Newtons studied about the gravity for a very long time and proposed theory about it.

Later on, based on his theories comes the gravitational law. His theory were based on various assumptions and examples that he related to explain the structure of universe.

His work shows how theories can become laws which are universally obeyed.

Ampère's law is the proper law to describe the magnetic field in a nonlinear wire, relating the circulation of the magnetic field to the electric current passing through the circuit. Hence option D is correct.

The law that describes the magnetic field in a nonlinear wire is Ampère's law. Ampère's law states that the magnetic field around an electric current is proportional to the current, with each segment of current contributing to the magnetic field. Specifically, it describes how the circulation of the magnetic field, or the line integral around a closed curve (denoted as C), is related to the electric current passing through the surface (denoted as S) that is bounded by the curve C. Importantly, the surface can be of any shape, allowing for the application of Ampère's law to wires of arbitrary configurations, including nonlinear wires.

Ox:vₓ=v₀

x=v₀t

Oy:y=h-gt²/2

|vy|=gt

tgα=|vy|/vₓ=gt/v₀=>t=v₀tgα/g

y=0=>h=gt²/2=v₀²tg²α/2g=>tgα=√(2gh/v₀²)=√(2*10*20/24²)=√(400/576)=0.83=>α=tg⁻¹0.83=39°

cosα=vₓ/v=v₀/v=>v=v₀/cosα=24/cos39°=24/0,77=31.16 m/s

Ec=mv²/2=2*31.16²/2=971.47 J=>Ec≈0.97 kJ

A. at the top of a hill

Final answer:

The roller coaster would have the greatest potential energy at the top of a hill, as potential energy is greatest at the highest point. Option A

Explanation:

The roller coaster would have the greatest potential energy at the top of a hill (option A). At the top of the hill, the roller coaster has the most potential energy because it is at the highest point and has the greatest ability to do work.

As the roller coaster goes down the hill, its potential energy is converted into kinetic energy, which is the energy of motion.

In terms of energy, potential energy is at its maximum at the top of the hill and decreases as the roller coaster moves down, while kinetic energy is at its minimum at the top of the hill and increases as the roller coaster gains speed. Option A

The force between two charges is proportional to the product of the charges.

If only one of the charges is reduced by a factor of 3, then the force is reduced by a factor of 3.

If both charges are reduced by a factor of 3, then the force is reduced by a factor of 9.

Answer: It is reduced by a factor of 3.

Explanation:

Answer:

Student showing the volume of cube

                      V = a³

                       if a = 3 cm

  Then volume is a³ = 3 ×3 × 3

                                 = 27 cm³

Thermal expansion occurs when the temperature of a material increases, leading to greater kinetic energy and separation between atoms, causing the material to expand in all dimensions.

For thermal expansion to occur in a material, the temperature of that material must increase. This increase in temperature results in an increase in the kinetic energy of the material's atoms or molecules. As discussed in the Kinetic Theory, in a solid, this kinetic energy manifests as small, rapid vibrations which cause atoms to push neighboring atoms or molecules slightly farther apart from each other.

An increase in the average separation between particles translates into an expansion of the material in all dimensions. This behavior is observed in everyday phenomena, such as the buckling of railroad tracks due to thermal expansion. The degree to which a material expands in response to temperature change can be quantified by its coefficient of thermal expansion, which generally varies with temperature.

the color violet has the shortest wavelength!

Answer: Violet! :D

Have a nice day :3

You must know the wavelength and the frequency.

Answer:

4 AU

Explanation:

We can solve the problem by using Kepler's third law, which states that the ratio between the square of the period of revolution of a planet around the Sun and the cube of its average distance from the Sun is constant for every planet orbiting the Sun:

[tex]\frac{T^2}{r^3}=k[/tex]

where

T is the orbital period

r is the average distance of the planet from the Sun

If we take two planets 1 and 2, the equation can be rewritten as

[tex]\frac{T_1^2}{r_1^3}=\frac{T_2^2}{r_2^3}[/tex]

In this problem, we have:

[tex]T_1 = 1 y[/tex] is the orbital period of the Earth

[tex]r_1 = 1 AU[/tex] is the distance of the Earth from the Sun

[tex]T_2 = 8 y[/tex] is the orbital period of the second planet

Therefore, we can re-arrange the equation to calculate r2, the averag distance of the other planet from the Sun:

[tex]\frac{r_2^3}{T_2^2}=\frac{r_1^3}{T_1^2}\\r_2 = \sqrt[3]{\frac{r_1 ^2 T_2^2}{T_1^2}}=\sqrt[3]{\frac{(1 AU)^3(8 y)^2}{(1 y)^2}} =4 AU[/tex]

Answer:

4

Explanation:

Potential energy is the store she energy from an object this could include rubber bands. Kinetic energy is the energy that deals with motion a good example is a person running

Hello There!

Potential energy is energy that is stored in an object. Kinetic energy involves motion so an object that has potential energy turns into kinetic energy.

An example could be a roller coaster going up a hill and it's building potential energy so when it goes down the hill, the potential energy will turn into kinetic energy.

The statement is false.  Balanced forces can NOT change the speed OR direction of an object's motion.  (See Newton's #1 law of motion.)

Answer:

False

Explanation:

As per Newton's first law of motion, an object will not change its state of motion until an external unbalanced force is applied on it.

If a balanced force is applied on an object there will be no change in state of motion. Take for example a box. One person moves it to left with force F and another person moves it to the right with same force F. The box will not move. But if the two forces are not equal then a net force will be acting on the box and it will move and its direction will be changed.

Answer:

9 m

Explanation:

The elastic potential energy initially stored in the spring is given by:

[tex]U=\frac{1}{2}kx^2[/tex]

where

k = 2500 N/m is the spring constant

x = 32 cm = 0.32 m is the compression of the spring

Substituting:

[tex]U=\frac{1}{2}(2500 N/m)(0.32 m)^2=128 J[/tex]

Due to the law of conservation of energy, when the spring is released all this energy is converted into kinetic energy of the rock, which starts moving upward. As the rock reaches its maximum height, all the energy has been converted into gravitational potential energy:

[tex]U=mgh[/tex]

where

m = 1.5 kg is the rock's mass

g = 9.8 m/s^2 is the gravitational acceleration

h = ? is the maximum height reached by the rock

Using U=128 J, we find h:

[tex]h=\frac{U}{mg}=\frac{128 J}{(1.5 kg)(9.8 m/s^2)}=8.7 m \sim 9 m[/tex]

Answer:

9m

Explanation:

got right on edg

From the law of Galileo Galilei  :v²=v₀²+2ad we take the speed

v²=0+2*4.90*200=1960=>v=√1960=44.27 m/s

Answer:

Change in the momentum of the car = 105 kgm/s

Explanation:

We have the Newton's second law, that is rate of change of momentum is force.

      [tex]\frac{dP}{dt}=F\\\\\frac{mv-mu}{dt}=F\\\\mv-mu=Fdt[/tex]

That is rate of change of momentum is impulse.

Here we need to find rate of change of momentum = Fdt

           dP = Fdt

            dP = 60 x 1.75 = 105 kgm/s

Change in the momentum of the car = 105 kgm/s

Given that:

k = 500 n/m,

work (W) = 704 J

spring extension (x) = ?

         we know that,

                      Work = (1/2) k x²

                          704 = (1/2) × 500 × x²

                            x = 1.67 m

A spring stretched for 1.67 m distance.

1 Continental drift

2 the layers of rock

One peice of evidence is fossils.  If similar fossils are in different continents like one is in soutch america and he other is in africa then how would the dino bones be apart? they can't swim...

The other is climates and land forms. Palentologist have found tropical plant fossils in an island of the Arctic ocean where it is way to cold for plants to even grow... Plants can't telaport....

#sHoOk ! EVIDENCE!!

Given data :

Work (W) = 1200 J ,

distance (S) = 20 m ,

Determine the Force applied to the box = ?

                  Work done = F. S

                            1200 = F . 20

                                  F = 60 N

Force applied to the box is 60 N

Should be the Lithosphere

Answer:

stove burner --> pan -- > bottom of pan handle --> top of pan handle

Explanation:

Conduction is one of the three methods of transfer of heat, and it occurs when the heat is transferred by contact/collisions between the molecules of two different mediums/objects (or also between molecules of different parts of the same object).

In this case, the transfer of heat by conduction occurs as follows:

- The stove burner is heated, and it is in contact with the pan --> the molecules of the stove burner move faster (they have more kinetic energy), so they transfer thermal energy (heat) by conduction to the molecules of the pan

- The pan is heated, and the same process occurs, but this time the heat is transferred to the bottom of the pan handle, which is attached to the pan

- Then, the bottom of the pan handle becomes hot, and by conduction heat is transferred also the part of the handle which is farther from the pan, so to the top part of the handle

Answer:

490 N

Explanation:

The elevator is rising at constant velocity: this means the acceleration of the system is zero, so according to Newton's second law, the net force on the system is also zero:

[tex]F_{net} = ma =0[/tex]

There are two forces acting on the person standing on the scale:

- its weight, downward, whose magnitude is W=490 N

- The normal force of the scale on the person, N, which is upward

Since the net force must be zero, we have:

[tex]W-N=0[/tex]

From which we find the normal force:

[tex]N=W=490 N[/tex]

The word problem is about finding the dimensions of a garden using a given amount of fencing material, applying the formula for the perimeter of a rectangle, and considering that the length is twice the width.

Imagine you have a small garden in the shape of a rectangle. The length of the garden is twice its width. You want to put a fence around the entire garden to keep the rabbits out. If you have 30 meters of fencing material available, what are the dimensions of your garden?

To solve this problem, we need to set up an equation using the formula for the perimeter of a rectangle, which is P = 2l + 2w, where P is the perimeter, l is the length, and w is the width. Since the length is twice the width, we can express the length as l = 2w. Substituting this into the perimeter formula gives us P = 2(2w) + 2w, which simplifies to P = 6w. Knowing the total perimeter is 30 meters, we can find the width using 30 = 6w, which yields w = 5 meters. The length, being twice the width, is then l = 10 meters.

Answer:

Alpha

Beta

Gamma

Answer: NO, IT'S GAMMA, BETA, THEN ALPHA

Explanation:

Answer:

[tex]1.51\cdot 10^5 J[/tex] of gravitational potential energy

Explanation:

the gravitational potential energy of an object is given by:

[tex]U=mgh[/tex]

where

m is the mass of the object

g is the acceleration due to gravity

h is the heigth of the object above the ground

In this problem, we have:

- m = 67 kg is the mass of the stove

- g = 9.8 m/s^2 is the acceleration due to gravity

- h = 230 m is the height of the stove above the ground

Substituting into the equation, we find

[tex]U=(67 kg)(9.8 m/s^2)(230 m)=1.51\cdot 10^5 J[/tex]

Answer: 5km by straight line, 7km by route.

Explanation:

The distance by route is 3km south and then 4km east, notice that the distances are perpendicular to each other, so the total distance traveled (by a straight line) is:

D = √((3km)^2 + (4km)^2) = √(9km^2 + 16km^2) = (√25)km = 5km

So the distance by a straight line that he needs to go back to where he started is 5km, and if he wants to get back by route, he must do 4km to the west and then 3km to the north, so a total of 7km