What did Bohr's model of the atom include that Rutherford's model did not have?
a nucleus
energy levels
electron clouds
smaller particles

Explanation:

a) Acceleration is the slope of the velocity vs time graph.  When velocity vs time is a straight line, that means the acceleration is a constant.  F = ma, so the resultant force is also constant.

b) As air resistance increases, the acceleration begins to decrease.

c) A falling object stops accelerating when it reaches terminal velocity.

d) F = ma, so when the acceleration is 0, the resultant force is also 0.

Answer:

E = 1440 kJ

Explanation:

It is given that,

Power of a cooker oven is 800 W

Voltage at which it is operated is 230 V

Time, t = 30 minutes = 1800 seconds

We need to find the electrical energy used by the cooker oven. The product of power and time is equal to the energy consumed. So,

[tex]E=P\times t\\\\E=800\ W\times 1800\ s\\\\E=1440000\ J\\\\\text{or}\\\\E=1440\ kJ[/tex]

So, electrical energy of 1440 kJ is consumed by the cooker oven.

Answer:

Creative thinking

Explanation:

As you can see in the question above, when Mandleev needed to organize the chemical elements in a logical, organized and efficient way, he thought until he came to the conclusion of organizing them according to the atomic weight of each one. This is a clear example of creative thinking, which is the term that refers to the act of solving a problem based on thought and reasoning.

Answer:

Creative thinking

Explanation:

Answer:

it will be 8ms-1

Explanation:

MaUa+MbUb=MaVa+MbVb

Answer:

Train accaleration = 0.70 m/s^2

Explanation:

We have a pendulum (presumably simple in nature) in an accelerating train. As the train accelerates, the pendulum is going move in the opposite direction due to inertia. The force which causes this movement has the same accaleration as that of the train. This is the basis for the problem.

Start by setting up a free body diagram of all the forces in play: The gravitational force on the pendulum (mg), the force caused by the pendulum's inertial resistance to the train(F_i), and the resulting force of tension caused by the other two forces (F_r).

Next, set up your sum of forces equations/relationships. Note that the sum of vertical forces (y-direction) balance out and equal 0. While the horizontal forces add up to the total mass of the pendulum times it's accaleration; which, again, equals the train's accaleration.

After doing this, I would isolate the resulting force in the sum of vertical forces, substitute it into the horizontal force equation, and solve for the acceleration. The problem should reduce to show that the acceleration is proportional to the gravity times the tangent of the angle it makes.

I've attached my work, comment with any questions.

Side note: If you take this end result and solve for the angle, you'll see that no matter how fast the train accelerates, the pendulum will never reach a full 90°!

Answer:

F = 1400 N

Explanation:

It is given that,

Mass of the ball, m = 70 kg

It is moving with an acceleration of 20 m/s². We need to find the force exerted by the ball.

Force is given by the product of mass and acceleration. So,

F = ma

[tex]F=70\ kg\times \ 20m/s^2\\\\F=1400\ N[/tex]

So, the force of 1400 N is exerted by a metal ball.

Answer:

In what way is iron unique among the elements?

It has the lowest mass per nuclear particle.

Match words at the left to the correct blanks in the sentences on the right. Not all words will be used.

-The energy that drives the expansion of a star into a subgiant or red giant comes from HYDROGEN SHELL FUSION

-Stars with mass greater than about 8 solar masses are considered HIGH-MASS STARS

-The final stage of core fusion in a low-mass star is HELIUM FUSION

-Stars that are fusing hydrogen in their cores are MAIN-SEQUENCE STARS

-When it dies, a high-mass star explodes as a SUPERNOVA

-A star that is expanding (into a subgiant and then a giant) has a(n) INERT HELIUM CORE

-When it dies, a low-mass star expels a PLANETARY NEBULA

-Stars with masses less than about two solar masses are considered LOW-MASS STARS

Answer:

The maximum torque, τ = 3.67 × 10⁻³ Nm

Explanation:

The torque τ = NiABsinθ where N = number of turns of circular coil = 50.5, i = current in circular coil = 22.5 mA = 0.0225 A, A = area of circular coil = πr² where r = radius of circular coil = 4.75 cm = 0.0475 m, B = magnetic field strength = 0.455 T and θ = 90° for maximum torque.

So, τ = NiABsinθ

τ = Niπr²Bsinθ

τ = 50.5 × 0.0225 A × π × (0.0475 m)² × 0.455 T × sin90°

τ = 0.003665 Nm

τ = 3.665 × 10⁻³ Nm

τ ≅ 3.67 × 10⁻³ Nm

So the maximum torque, τ = 3.67 × 10⁻³ Nm

Answer:

The formula for speed is speed=distance

time

Explanation:

to work out what the units are for speed,you need to know the units for distance and time.In this example,distance is in metres(m) and time is in seconds (s) , so the units for speed is metre per second (m/s).

Answer:

2

yes

Explanation:

been submitted to the Theme 20 participants will be there was a lot of fun and I will be there at Home

Explanation:

It is given that,

The distance covered by a body along the x-axis is given by :

[tex]x=2t^3+5t^2+t[/tex]

t is in seconds and x is meters

Speed of the body is given by :

[tex]v=\dfrac{dx}{dt}\\\\v=\dfrac{d(2t^3+5t^2+t)}{dt}\\\\v=6t^2+10t+1[/tex]

At t = 0,

[tex]v=6(0)^2+10(0)+1=1\ m/s[/tex]

At t = 2 s,

[tex]v=6(2)^2+10(2)+1=45\ m/s[/tex]

So, the average speed in a time interval from t= 0s and t=2s is 45 m/s.

Answer:

Explanation:

Given that:

For a first order instrument with a sensitivity of .4 mV/K

constant c  = 25 ms = 25 × 10⁻³ s

The initial temperature [tex]T_1[/tex] = 273 K

The final temperature [tex]T_2[/tex] = 473 K

The initial volume = 0.4 mV/K × 273 K = 109.2 V

The final volume =  0.4 mV/K × 473 K =  189.2 V

the instrument’s response as a function of time for a sudden temperature increase can be computed as follows:

Let consider y to be the function of time i.e y(t).

So;

y(t) = 109.2  + (189.2 - 109.2)( 1 - [tex]\mathbf{e^{-t/c}}[/tex])mV

y(t) = (109.2 +  80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV

Plot the response y(t) as a function of time.

The plot of y(t) as a function of time can be seen in the diagram  attached below.

What are the units for y(t)?

The unit for y(t) is mV.

Find the 90% rise time for y(t90) and the error fraction,

The 90% rise time for y(t90) is as follows:

Initially 90% of 189.2 mV = 0.9 ×  189.2 mV

=  170.28 mV

170.28 mV = (109.2 +  80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV

170.28 mV - 109.2 mV = 80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV

61.08 mV =  80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV

0.7635  mV = ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV

t = 1.44 × 25  × 10⁻³ s

t = 0.036 s

t = 36 ms

The error fraction = [tex]\dfrac{189.2-170.28 }{189.2}[/tex]

The error fraction = 0.1

The error fraction = 10%

Answer: 37.5 km

Explanation:

The question is that

If you ran 15 km/hr for 2.5 hours, how much distance would you cover ?

Where

Speed = 15 km/ hr

Time = 2.5 hours

Using the formula for speed.

Speed = distance/time

Substitute speed and time into the formula

15 = distance/ 2.5

Make distance the subject of formula by cross multiplying.

Distance = 15 × 2.5

Distance = 37.5 km.

Answer:

Explanation:

Energy of gamma ray = 2.2233 MeV

Let mass of neutron be n  amu  

mass defect of deuteron = 2.013553212 - ( 1.007 276 467 + n ) u .

in terms of energy this mass defect will be equal to energy of gamma ray

1 amu = 931 MeV

931 [ 2.013553212 - ( 1.007 276 467 + n ) ] =  2.2233

( 1.007 276 467 + n ) -  2.013553212  = .00238807733

n = 1.008664822 amu

so mass of neutron = 1.008664822 amu

Answer:

The expected time is 2.28 hours.

Explanation:

The speed of storm = 35 km/hr

The distance between the house and the storm = 80 km.

Now, we have to find the time taken by storm to arrive at the house. Here, we can determine the time by dividing the distance with speed.

The time, taken by storm =  Distance/speed

The time, taken by storm = 80 / 35

The time, taken by storm = 2.28 hours.

Answer: A. 2.7 x 10^2 joules

Explanation: I’m sorry for the guy above me!

Answer:

[tex] \boxed{\sf Work \ done = 4 \ J} [/tex]

Given:

Force = 8 N

Distance covered by the body = 50 cm = 0.5 m

Explanation:

Work Done = Force × Distance covered by the body

= 8 × 0.5

= 4 J

Answer:

λ = 2.5m

Explanation:

Given the following :

Speed of sound (v) = 10m/s

If 5 oscillations pass through a point in 0.5seconds;

Time taken (period) for 1 oscillation is :

Number of oscillations / total time taken

5 / 0.5 = 0.25 seconds

Wavelength, period and Velocity are related by the formula:

v = λ / T

λ = v * T

λ = 10 * 0.25

λ = 2.5 m

Answer:

30 miles people hour (mph)

Explanation:

The maximum speed for one flat tyre is 30mph, for both tyres it is 20 mph and for two tyres on the same side it is 30mph. When a tyre is punctured driving at high speed should be avoided and not too long distance should be covered to avoid further accident and for the safety of other vehicles. Speed limit and distance for flat tires should be strictly followed.

Answer:

Explanation:

beacuse the poles are the cause of graIt's due to the rotation of earth about its own axis. Due to the rotation, objects placed on the surface of earth also rotates . Their rotational kinetic energy prevents them from the free fall along gravitational pull. This phenomena can also be explained sitting on the earth surface as their free fall suffers a centrifugal barrier due to the rotation. In this explanation, the term, centrifugal barrier, appears because earth is a non-inertial frame. Centrifugal force in a non intertial frame acts opposite to gravitational force.

The rotational energy / centrifugal barrier on a object depends on the radius of the circle linearly ; the circle is drawn around the axis of rotation from the point where the object placed. Now you can imagine that its radius get shorter and shorter towards the pole from the equator. Hence the barrier decreases if we move from equator to the both poles of earth. Hence garvitational force on a object i.e. its weight, so the g, becomes effectively maximum on the poles and minimum on the equator.

Answer:

The mass of the object and its height in the gravitational field of the Earth.

Explanation:

If we are talking about gravitational potential energy which is defined as:

[tex]U=m\,*\,g\,*\,h[/tex]

being "m" the object's mass, "g" the acceleration due to gravity, and "h" the height at which the object is located relative to the conventionally picked level for zero of potential energy.

As long as the value of "g" is constant, the only two variables that determine the gravitational potential energy are the mass (m) of the object and its relative height (h).

Answer:

The objects weight and height above Earth's surface

Explanation:

K12 :)

Answer:

80 N.

Explanation:

The following data were obtained from the question:

Mass (m) = 20 Kg

Initial velocity (u) = 5 m/s

Final velocity (v) = 17 m/s

Time (t) = 3 secs

Force (F) =.?

Next, we shall determine the acceleration of the body.

Acceleration is simply defined as the rate of change of velocity with time. Mathematically, it is expressed as:

Acceleration = change of velocity /time

Acceleration (a) = (final velocity (v) – initial velocity (u)) / time (t)

a = (v – u) /t

With the above formula, we can obtain the acceleration of the body as follow:

Initial velocity (u) = 5 m/s

Final velocity (v) = 17 m/s

Time (t) = 3 secs

Acceleration (a) =?

a = (v – u) /t

a = (17 – 5) /3

a = 12/3

a = 4 m/s²

Finally, we shall determine the force applied to the body as follow:

Force (F) = mass (m) x acceleration (a)

F = ma

Mass (m) = 20 Kg

Acceleration (a) = 4 m/s²

Force (F) =.?

F = ma

F = 20 x 4

F = 80 M.

Therefore, the force applied on the body is 80 N.

Explanation:

Volume is the amount of space an object takes up, while mass is the amount of matter in an object. ... To find the volume of an irregular sized object, one would use the displacement method for measuring volume and place the object in water and measure the amount of water that is displaced.

Answer:

To measure the volume of an irregularly shaped object, pour some water in a measuring cylinder. Then suspend the irregularly shaped object with a thread. After that , move the object gradually downwards and immerse it in water. The volume of the irregularly shaped object is the difference between the volume of the liquid before and after. After measuring the difference, we come to know about the volume of the irregularly shaped object.

Answer:

Balanced forces

Explanation:

Answer:

its balance force

Explanation:

Answer:

The dust present in the clouds.

Explanation:

The complicated composition molecules that can be found in space are generally associated with clouds of dust. The significant amount of dust in these clouds provides protection not only for these molecules, but for any body that makes up or is associated with dust clouds.

It is exactly this dust that protects the molecules against the action of ultraviolet rays.

Answer:

The correct option is;

a. 12.5 g

Explanation:

The given parameters are;

The initial mass of the radioactive substance = 200 g

The half life of the radioactive substance = 50 years

The time duration for the disintegration = 200 years

The formula for half life is given as follows;

[tex]N(t) = N_0 \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{1/2}}[/tex]

Where:

N(t) = Quantity of the remaining substance

N₀ = Initial radioactive substance quantity  = 200 g

t = Time duration  = 200 years

[tex]t_{1/2}[/tex] = Half life of the radioactive substance  50 years

Therefore, we have;

[tex]N(t) =200 \times \left (\dfrac{1}{2} \right )^{\dfrac{200}{50} } =200 \times \left (\dfrac{1}{2} \right )^4 = 12.5 \ g[/tex]

Therefore, at the end of 200 years, the quantity left = 12.5 g.

Answer:

C) 1.5 A

Explanation:

P = IV

180 W = I (120 V)

I = 1.5 A

Answer:

b. varies inversely with the square of the distance from the center of Earth.

Explanation:

Comparing the Newton's law of universal gravitation and second law of motion;

from Newton's second law of motion,

F = ma ............. 1

from New ton's law of universal gravitation,

F = [tex]\frac{GMm}{r^{2} }[/tex] ........... 2

Equating 1 and 2, we have;

mg =  [tex]\frac{GMm}{r^{2} }[/tex]

g = [tex]\frac{GM}{r^{2} }[/tex]

Therefore, the acceleration due to gravity near Earth, g, is inversely proportional to the square of the distance from the center of Earth.

Answer:

449.38 J

Explanation:

ΔS = ΔQ/T

Where ΔS = entropy change

Q = quantity of heat

T = temperature

First reservoir :

T = –30°C = - 30 + 273 = 243K

Q = 400 J

Second reservoir :

T = 0°C = 273K

Q =?

To have same increase in entropy for both reservoirs :

Q/T of first reservoir = Q/T of second reservoir

400/243 = Q/273

243 * Q = 400 * 273

Q = (400 * 273) / 243

Q = 109,200 / 243

Q = 449.38271

Q = 449.38 J

Answer:

a=845.07 m/s2

Explanation:

m=0.142kg

F=120N

a=?

F=m*a /:m

a=F/m

a=120N/0.142kg

a=845,07m/s2

Answer:

a = 845.07 m/s²

Explanation:

As we know ,

as per newton's 2nd law:-

F = ma

therefore

a = F/m

given:

a = ?

F = 120N

m = 0.142 kg

procedure:-

a = 120/0.142

therefore :

a = 845.07 m/s²