Answer:
The atom is mostly empty space.
Explanation:
Ernest Rutherford in the year 1911 developed a model of an atom. In his model the atom was shown that the atom is mostly empty spaces composed of negative electrons which orbits round a positive nucleus just like planets revolving round the sun.
Rutherford came up with this model by performing experiments in 1909 which involves the scattering of alpha particles on a thin gold foil. From this experiments he came up with his model.
Answer:
A!
Explanation:
The atom is mostly empty space.
what is SI unit System ? why has SI system been developed ? Give reasons
Explanation:
SI is the international system of units
It was developed to express magnitudes and quantities
A spring of initial length 35 cm acquires a length of 55 cm when we hang from it a mass of 3.5 kg. Calculate:
a) The elastic constant of the spring.
b) The length of the spring when we hang a mass of 5 Kg.
Answer:
the elastic constant of the spring=1.715
the length of the spring=0.28
Explanation:
we know that according to hooks law
F=-k x
F= force
k= elastic constant
x= extension or compression
given
length change from 35cm to 55 cm so delta x = L2-L1= 55-35=20 cm
now to find k we need F and F =ma
M for part a is 3.5 kg
so F=3.5 kg *9.8=34.3
now k=F/x
k=34.3/20=1.715 N/cm=171.5 N/m
now to find length given mass is 5 kg so
F= ma
F=5*9.8=49 N
so x =F/k
x=49/171.5
x=0.28
A group of Advanced Open Water Divers plans to make two dives. The first dive is on a reef in 90 feet of water for 20 minutes. The group then remains on the surface for 1 hour. The second dive is on a wreck in 60 feet of water, with a planned bottom time of 30 minutes. What will be the ending pressure group after the second dive
Answer:
The ending pressure is R.
Explanation:
This is Recreational scuba diving (R). According to standards, this diving has prescribed depth limit of 130 ft. This means that the limit must include a depth that is not greater than 130 ft while using only compressed air and not even requiring a decompression stop.
Now, from the question, we can see that that there was a prescribed limit of 60ft of water with a planned bottom time of 30 minutes.
Thus, the ending pressure is R.
What did Bohr's model of the atom include that Rutherford's model did not have?
a nucleus
energy levels
electron clouds
smaller particles
Answer:
The correct option is energy levels
Explanation:
Rutherford's model of an atom suggests that an atom has a tiny positively charged central mass (now called the nucleus) which is surrounded by electrons (negatively charged) in a cloud-like manner.
Bohr's model went a bit further than the Rutherford's model in describing an atom by suggesting that the electrons which surrounds in the nucleus travel in fixed circular orbits. This description by Bohr was able to describe the energy levels of orbitals which assumes that smallest orbitals have the lowest energy while the largest orbitals have the highest energy.
Answer:
energy levels
hope this helped!
Explanation:
A metal disk lies in the xy-plane, centered about the origin, and rotates with a constant angular velocity about the z-axis. There is a uniform 0.0314 T magnetic field parallel to the z-axis. The radius of the disk is 1.56 m. At what rate is the disk turning if an E of 3.86 V develops between the center of the disk and a point on its rim
Answer:
w = -101 rad / s
Explanation:
For this exercise we will use Faraday's law
E = - dФ / dt
where the magnetic flux is
Ф = B. A = B A cos θ
In this case, the angle between the magnetic field and the normal to the disk is zero, cos 0 = 1, they indicate that the field is constant, let's find the area
The area rotated by the disk is
A = ½ r s
if we express the angles in radians
θ = s / r
s = r θ
where is the arc supported
A = ½ r (r θ)
let us substitute in the Faraday equation
E = - d (B ½ r² θ) / dt
E = - ½ B r² dθ/dt
the definition of angular velocity is
w = dθ/dt
E = - ½ B r² w
w = - 2E / B r²
let's calculate
w = - 2 3.86 / (0.0314 1.56²)
w = -101 rad / s
At what altitude the value of ‘g’ would become one fourth (¼)of the surface of the earth?
Answer:
Explanation:
For acceleration due to gravity g , the expression is
g = GM / R² , where G is gravitational constant M is mass of the earth and R is radius of the earth .
At height h , let the value of it becomes g / 4 , so
g / 4 = GM / ( R + h )²
dividing
4 = [( R+ h)² / R² ]
2 = (R + h) / R
2 = 1 + h / R
h / R = 1
h = R
So at height equal to radius of the earth , acceleration due to gravity becomes 1 /4 of value on the surface of the earth .
An average skater averages 11 m/s over the first 5 seconds of a race. find the average speed required over next 10 seconds to average 12 m/s overall.
Answer:
usa
Explanation:
What is pin hole camera?
Answer:
Explanation:
Pinhole camera is a simple camera. It does not have a lens. The light passes from a hole and an inverted image is formed on the opposite side of the box.
Comic-strip hero Superman meets an asteroid in outer space and hurls it at 800 m/s, as fast as a bullet. The asteroid is a thousand times more massive than Superman. In the strip, Superman is seen at rest after the throw. Taking physics into account, what would be his recoil speed (in km/s)?
Answer:
800km/s
Explanation:
Initial momentum = final momentum
the total momentum is zero, Before the release of the asteroid , but Superman and the asteroid are not moving.
So, according to the Conservation of momentum the total momentum when the astronaut is been thrown will equals to zero . Then we can say
Initial momentum = final momentum
Because the momentum of the Superman immediately the asteroid is been thrown is equal to the momentum of the asteroid
Momentum =(mass ×velocity)
the mass of the asteroid i= 1000M
Given velocity = 800 m/s,
momentum =(1000M)(800 m/s)
= 800,000M m/s.
to get the answer, we need to divide by Superman's mass, M, which gives his recoil velocity of 800,000 m/s.
But we're told to convert to km/ s
We know that 1m/s=0.001km/s
=(800,000M m/s)× (0.001km/s)
=800km/s
Therefore, his recoil speed (in km/s) is 800km/s
A missile is moving 1350 m/s at a 25° angle it needs to hit a target 23,500 m away in a 55° direction in 10.2 seconds what is the magnitude of its final velocity
Answer:
3504 m/s
Explanation:
Let x be the horizontal component of distance
y - vertical component of distance
t-time
ax- horizontal component of acceleration
ay-Vertical component of acceleration
Vx-horizontal component of velocity
Vy-Vertical component of velocity
horizontally: x = V_x ×t + ½×a_x×t²
plugging the values we get
23500× cos 55º = 1350×cos25.0º × 10.20 + ½×a_x× (10.20)²
⇒ax = 19.2 m/s²
Moreover,
V'x = V_x + a_x×t = 1350×cos25.0º + 19.2×10.20= 1419 m/s
similarly in vertical direction:
y = V_y×t + ½×a_y×t²
23500×sin55º = 1350×sin25.0º×10.20s + ½×a_y×(10.20)²
⇒a_y = 258 m/s²
Also,
V'y = V_y + a_y×t = 1350×sin25.0º + 258×10.20 = 3204 m/s
Therefore
V = √(V'x² + V'y²) = 3504 m/s
therefore, magnitude of final velocity of missile=3504 m/s
THANKS
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Brainliest
What form of energy does a block of chocolate have?
Answer:
Chemical Energy
Explanation:
The transmutation of a radioactive uranium isotope, 234/92U , into a radon isotope, 222/86Rn , involves a series of three nuclear reactions. At the end of the first reaction, a thorium isotope,230/90Th , is formed and at the end of the second reaction, a radium isotope, 226/88Ra , is formed. In both the reactions, an alpha particle is emitted. Write the balanced equations for the three successive nuclear reactions.
Answer:
See explanation below
Explanation:
234/92U--------> 230/90Th + 4/2He
230/90Th----->226/88Ra + 4/2He
There are various modes of radioactive decay. One of them is alpha decay.
Alpha decay involves the loss of an alpha particle from a nucleus. When this occurs, the mass number of the daughter nucleus is four units less than that of the parent while the atomic number of the daughter nucleus is two units less than that of its parent as shown in the equations above.
An alpha particle is akin to a helium nucleus in terms of mass and charge
A body decelerates uniformly to a constant speed and after some time it accelerates uniformly Draw the shape of speed time graph for such a motion . Label the three sections of this graph. What is the quantity which is measured by the area occupied under speed time graph ?
Answer:
here I am just giving an idea of how the graph will be like ...
In the pic..
Hope it helped u if yes mark me BRAINLIEST!
Tysm!
:)
An atom of unknown element Z has mass number of 39 and an atomic number of 18. How many protons and how many neutrons are in this atom? Show your work
Answer:
proton:18
neutron:39-18=21
A fish inside the water 12cm below the surface looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 4/3 the radius of circle is
Answer:
13.6 cm
Explanation:
From Snell's law:
n₁ sin θ₁ = n₂ sin θ₂
In the air, n₁ = 1, and light from the horizon forms a 90° angle with the vertical, so sin θ₁ = sin 90° = 1.
Given n₂ = 4/3:
1 = 4/3 sin θ
sin θ = 3/4
If x is the radius of the circle, then sin θ is:
sin θ = x / √(x² + 12²)
sin θ = x / √(x² + 144)
Substituting:
3/4 = x / √(x² + 144)
9/16 = x² / (x² + 144)
9/16 x² + 81 = x²
81 = 7/16 x²
x ≈ 13.6
The distance from the Earth to the Sun equals 1 AU. Neptune is 30 AU from the Sun. How far is Neptune from the Earth? AU
Answer:
The answer is 29 AU
Hoped I helped
mark me as brainliest
Answer:
29
Explanation:
One glass microscope slide is placed on top of another with their left edges in con- tact and a human hair under the right edge of the upper slide. As a result, a wedge of air exists between the slides. An interference pattern results when monochromatic light is incident on the wedge. What is observed at the left edge of the slides? a. A dark fringe b. A bright fringe c. Impossible to determine
Answer:
A dark fringe
Write the relation between:
1) applied force and pressure.
2) surface area of contact and pressure.
realtion between applied force.and pressure is more force exerts more pressure whereas less force exerts less pressure
confused in another one
Answer:
See below
Explanation:
1) Applied Force and Pressure
Pressure = Force / Area
This shows that Applied force and pressure are in direct relationship. This means that If the Applied force is more, the Pressure is also More and vice versa.
2) Surface Area of Contact and Pressure
Pressure = Force / Surface Area of Contact
This shows that Pressure and Surface area of contact are inversely related. This means that if pressure is increased on an object, the surface area of contact decreases and vice versa.
Can someone explain how the weight of the block is 10.26N, with reference to an appropriate law of motion?
this process is called parellelogram method of resolving vectors.
A high-voltage powerline operates at 500000 V-rms and carries an rms current of 500 A. If the resistance of the cable is 0.050Ω/km, what is the resistive power loss in 200 km of the powerline?
Answer:
2,500,000W or 2.5MW
Explanation:
The power lost due to resistance is given by I^2R. We must first obtain R as follows;
Resistance per kilometer= 0.050Ω/km
Distance covered= 200km
R = 200km x 0.050Ω/km = 10Ω
The lost power as a 500A current passes through the powerline is:
P = I²R
P= 500² x 10
P= 2,500,000 W or 2.5MW
The resistive power loss in 200 km of the powerline is of 2.5 MW.
Given data:
The root mean square voltage is, V' = 500000 V.
The magnitude of current through the power line is, I =500 A.
The magnitude of resistance of cable is, R = 0.050 Ω/km.
The length of powerline is, L = 200 km.
Whenever there is a flow of current through the wire, then there are various losses out of which the power loss is a major factor. The mathematical expression for the power loss is given as
P = I²R
Solving as,
P= 500² x 10
P= 2,500,000 W or 2.5MW
Thus, we can conclude that the resistive power loss in 200 km of the powerline is of 2.5 MW.
Learn more about the resistive power loss here:
https://brainly.com/question/15158529
THE LENGTH OF A PENDULUM IS (1.5±0.01)m AND THE ACCELERATION DUE TO GRAVITY IS TAKEN AS (9.8±0.1)ms-² calculate the time period of the pendulum with uncertainty in it
Answer:
2.4583 ± 0.0207 seconds
Explanation:
The time period of a pendulum is approximately given by the formula ...
T = 2π√(L/g)
The maximum period will be achieved when length is longest and gravity is smallest:
Tmax = 2π√(1.51/9.7) ≈ 2.47903 . . . seconds
The minimum period will be achieved for the opposite conditions: minimum length and maximum gravity:
Tmin = 2π√(1.49/9.9) ≈ 2.43756 . . . seconds
If we want to express the uncertainty using a symmetrical range, we need to find half their sum and half their difference.
T = (2.47903 +2.43756)/2 ± (2.47903 -2.43756)/2
T ≈ 2.4583 ± 0.0207 . . . seconds
__
We have about 2+ significant digits in the given parameters, so the time might be rounded to 2.46±0.02 seconds.
A construction worker uses an electrical device to attract fallen nails and sharp objects
from a construction site. What is causing the attraction of the metal objects?
O An electrical wave oscillating perpendicular to the electrical device.
O An electrical charge radiating perpendicular to the wire
O Amagnetic wave radiating perpendicular to an electrical device
O A magnetic wave and electrical current moving in opposite directions
Answer:
is the last one, a magnetic wave and electrical current moving in opposite directions
Explanation:
opposite directions always attract in magnetic waves and fields
PLZ HELP ASAP!!!! THANK YOU The disturbance that occurs as longitudional waves travel through a medium can be described as a series of A:oscillations and refractions B:propagations and compressions C:destructions and constructions D:rarefactions and compressions
Answer:
D:rarefactions and compressions
Explanation:
Longitudinal waves are readily formed in materials such as a stretched spring. Longitudinal waves are waves which travel in a direction parallel to the vibrations of the medium.
Longitudinal waves are characterized by a series of compressions and rarefactions. The compressions are areas of clusters while rarefactions are areas of expansions. The same can be observed in a sound wave.
A 0.149 kg glider is moving to the right on a frictionless, horizontal air track with a speed of 0.710 m/s . It has a head-on collision with a 0.308 kg glider that is moving to the left with a speed of 2.27 m/s . Suppose the collision is elastic.1. Find the magnitude of the final velocity of the 0.157kg glider.
2. Find the magnitude of the final velocity of the 0.306kg glider.
Answer:
v1 = −2.201946 m/s ( to the left)
v2 = 0.7780534 m/s ( to the right)
Explanation:
Given the following :
Mass of first glider (m1) = 0.149kg
Initial Speed of first glider (u1) = 0.710 m/s
Mass of second glider (m2) = 0.308kg
Initial Speed of second glider (u2) = 2.27m/s
For elastic collision:
m1u1 + mu2u2 = m1v1 + m2v2
Where V1 and v2 = final velocities if the body after collision.
Taking right as positive ; left as negative
u1 = 0.710m/s ; u2 = - 2.27m/s
u1 - u2 = - (v1 - v2)
0.710 - - 2.27 = - v1 + v2
v2 - v1 = 2.98 - - - - (1)
From:
m1u1 + mu2u2 = m1v1 + m2v2
(0.149 * 0.710) + ( 0.308 * - 2.27) = (0.149 * v1) + (0.308 * v2)
0.10579 + (-0.69916) = 0.149 v1 + 0.308v2
−0.59337 = 0.149 v1 + 0.308v2
Dividing both sides by 0.149
v1 + 2.067v2 = −0.59337 - - - - - (2)
From (1)
v2 = 2.98 + v1
v1 + 2.067(2.98 + v1) = −0.59337
v1 + 6.16 + 2.067v1 = −0.59337
3.067v1 = −0.59337 - 6.16
3.067v1 = −6.75337
v1 = −6.75337 / 3.067
v1 = −2.201946 m/s ( to the left)
From v2 = 2.98 + v1
v2 = 2.98 + (-2.201946)
v2 = 0.7780534 m/s ( to the right)
Den pushes a desk 400 cm across the floor. He exerts a force of 10 N for 8 s to move the desk. What is his power output? (Power: P = W/t) 1.25 W 5 W 40 W 500 W
Answer:
5 W
Explanation:
The formula of the power is:
● P = W/t
W is the work and t is the time needed to do it(in seconds)
Let's calculate first the work that the force exerced:
W = Vector F . Vector d
D is the distance ( here 400 cm wich is 4 m)
Make a representation to see how are the vectors F and V.(picture below)
The vector F and d are colinear since Den is pushing the desk on the ground.
● W = 4 × 10 = 40 J
J is Joule
■■■■■■■■■■■■■■■■■■■■■■■■■■
● P = W / t
● P = 40/ 8
● P = 5 W
The power output of the force of 10N for 8 seconds to move the desk is 5 watts. Thus, the correct option is B.
What is Power?Power is the amount of energy which is transferred or converted per unit time. In the SI system of Units, the unit of power is the watt, which is equal to one joule per second time.
We Know, P = W/t
where, P = Power,
W = Work done,
t = Time taken
P = F × s/t
where, F = Force applied,
s = distance travelled,
t = time taken
Here, F = 10N
s = 400cm = 4m
t = 8 sec
Substitute their values into the expression,
P = 10 × 4/8
P = 10 × 1/2
P = 5 Watt
So, the power output will be 5 watts.
Therefore, the correct option is B.
Learn more about Power here:
https://brainly.com/question/287674
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A long, straight, horizontal wire carries a left-to-right current of 40 A. If the wire is placed in a uniform magnetic field of magnitude 3.7 ✕ 10−5 T that is directed vertically downward, what is the resultant magnitude of the magnetic field 22 cm above the wire (in T)?
Answer:
The magnitude of the resultant of the magnetic field is [tex]4.11\times10^{-5}\ T[/tex]
Explanation:
Given that,
Current = 40 A
Magnetic field [tex]B=3.7\times10^{-5}\ T[/tex]
Distance = 22 cm
We need to calculate the magnetic field
Using formula of magnetic field
[tex]B'=\dfrac{\mu_{0}I}{2\pi r}[/tex]
Where, r = distance
I = current
Put the value into the formula
[tex]B'=\dfrac{4\pi\times10^{-7}\times20}{2\pi\times0.22}[/tex]
[tex]B'=1.8\times10^{-5}\ T[/tex]
We need to calculate the magnitude of the resultant of the magnetic field
Using formula of resultant
[tex]B''=\sqrt{B^2+B'^2}[/tex]
Put the value into the formula
[tex]B''=\sqrt{(3.7\times10^{-5})^2+(1.8\times10^{-5})^2}[/tex]
[tex]B''=4.11\times10^{-5}\ T[/tex]
Hence, The magnitude of the resultant of the magnetic field is [tex]4.11\times10^{-5}\ T[/tex]
3) A charged particle is moving with velocity of V in a magnetic field of B, which one of the followings is correct: A) The direction of force F on the charge is parallel to magnetic field B B) The direction of force F on the charge is parallel to velocity direction V C) The force is maximized when velocity direction and magnetic field are parallel D) The force F is perpendicular (normal) to both velocity V and magnetic field B E) The direction of force on positive charge or negative charge would be the same
Answer:
D) The force F is perpendicular (normal) to both velocity V and magnetic field B.
Explanation:
When a charged particle enters a magnetic field, it experiences a force which changes its direction of travel. The direction of motion of the charged particle, the magnetic field direction, and the direction of the force, are all perpendicular to one another. According to Lorentz right hand rule, hold the right hand parallel to the ground, with the palm facing up, and the thumb held out at right angle to the other fingers. If the direction of the other fingers represents the magnetic field line and direction, and the thumb represents the direction of motion of a positively charged particle, then, the palm will push up in the direction of the force. For a negatively charged particle, the force will push down in the direction of the back of the hand.
PLS HELP ME Define Derived Quantities ?
Derived Quantities
Explanation: Those physical quantities which are derived from fundamental quantities are called derived quantities and their units are called derived units. e.g., velocity, acceleration, force, work etc.
Answer:
These are quantities calculated from two or more measurements
Explanation:
They can't me measured directly.
They can only be computed.
They are calculated in PHYSICAL SCIENCE.
hope it helps.
A mass, M, is at rest on a frictionless surface, connected to an ideal horizontal spring that is unstretched. A person extends the spring 30 cm from equilibrium and holds it at this location by applying a 10 N force. The spring is brought back to equilibrium and the mass connected to it is now doubled to 2M. If the spring is extended back 30 cm from equilibrium, what is the necessary force applied by the person to hold the mass stationary there
Answer:
The necessary force applied by the person to hold the mass stationary there is 10 N
Explanation:
We are told that this person extends the spring 30 cm from equilibrium and holds it at this location by applying a 10 N force.
Thus, based on Hooke's law formula which is F = k Δx, we can say that the mass attached to the spring does not change the spring constant. Thus, the
same resistive spring force will still be in place and in turn, the same stretching force of 10N would still be required.
Thus;
The necessary force applied by the person to hold the mass stationary there is 10 N
You have a cup with 50cm filled with water. How much pressure will the water act on the bottom of the cup? The density of water is 1000kg/m^3 and g = 10N/kg
Answer:
5000 N/m².
Explanation:
The following data were obtained from the question:
Density (d) = 1000 kg/m³
Acceleration due to gravity (g) = 10 N/kg
Height (h) = 50 cm = 50/100 = 0.5 m
Pressure (P) =.?
Pressure is related to density and height by the following equation:
P = dgh
Where
P is the pressure.
d is the density.
g is the acceleration due to gravity.
h is the height.
With the above formula, we can obtain the pressure at the bottom of the cup as follow:
P = dgh
P = 1000 x 10 x 0.5
P = 5000 N/m²
Therefore, the pressure at bottom of the cup is 5000 N/m².
