Please round 1045.2 to three significant digits

Room heaters are placed on the floor of a room so that the air heated by it rises up and sets up the convection current in the room quickly and uniformly.

Answer:

góc phản xạ 15°

Explanatin

Answer:

0.6 m/s

Explanation:

The details of the masses and velocities are;

The mass of the ice skater, m₁ = 80 kg

The mass of the ball, m₂ = 8 kg

The speed with which the skater tosses the ball forward, v₂ = 6 m/s

Therefore;

According to the principle of conservation of linear momentum, we have;

m₁·v₁ = m₂·v₂

Where;

v₁ = The skater's reactive velocity

Therefore, we get;

80 kg × v₁ = 8 kg × 6 m/s

v₁ = 8 kg × 6 m/s/(80 kg) = 0.6 m/s

The skater's reactive velocity, v₁ = 0.6 m/s.

Answer:

Mass M = 100 kg

Explanation:

Given;

Net force = 400 N

Initial velocity u = 66 km/h

Final velocity v = 30 km / h

Time taken = 2.5second

Find:

Acceleration of this object a

Mass M

Computation:

1 km/h = 0.277778 m/s

So,

Initial velocity u = 66 km/h = 18.333

Final velocity v = 30 km / h = 8.333

Acceleration of this object a = [v - u]/t

Acceleration of this object a = [8.333 - 18.333]/2.5

Acceleration of this object a = -4 m/s²

Mass M = Force / Acceleration of this object a

Mass M = 400 / 4

Mass M = 100 kg

Answer:

the group of units suggested by the international convention of scientists in 1960 AD to make similarties in meseurment all over the world is called SI units

Answer:

The ratio of energy of AA battery to the car battery is 0.0156.

Explanation:

An AA battery (remote control battery) supplies the circuit with 1.5V, while a car battery supplies 12V. What is the relationship between the energy supplied between these circuit elements?

Supply by AA battery = 1.5 V

Supply by car battery = 12 V

The resistance of the circuit is R.

The energy supplied = V^2/R

The energy supplied by the AA battery is

E = 1.5 x 1.5 / R = 2.25/R

The energy supplied by the car battery is

E' = 12 x 12/ R = 144 / R

So, the ratio of

E : E' = 2.25 : 144 = 0.0156  

Answer:

The height reached is 20m, The time taken to reach 20m is 2 seconds

Explanation:

Observing the equations of motion we can see that the following equation will be most helpful for this question.

[tex]v^{2} = u^{2} + 2as[/tex]

We are given initial velocity, u

We know that the stone will stop at its maximum height, so final velocity, v

Acceleration, a

And we are looking for the displacement (height reached), s

Substitute the values we are given into the equation

[tex]0^{2} = 20^{2} + 2(10)s[/tex]

Rearrange for s

[tex]0^{2} -20^{2} =20s[/tex]

[tex]-400=20s[/tex]

[tex]\frac{-400}{20} =s[/tex]

s = -20 (The negative is just showing direction, it can be ignored for now)

The height reached is 20m

Use a different equation to find the time taken

[tex]s = vt - \frac{1}{2} at^{2}[/tex]

Substitute in the values we have

[tex]-20=(0)t - \frac{1}{2} (10)t^{2}[/tex]

Rearrange for t

[tex]-20 =0 -5 t^{2}[/tex]

[tex]\frac{-20}{-5} =t^{2}[/tex]

[tex]4 = t^{2}[/tex]

t = 2s

The time taken to reach 20m is 2 seconds

Answer:

the answer is ....angle of reflection

Answer:

[tex]W=3456 N[/tex]

Explanation:

Force 1 [tex]F_1=3456[/tex]

Force 2 [tex]F_2=2333N[/tex]

Acceleration at stage 2 [tex]a_2=0.39[/tex]

Generally the weight of the Craft W is given as

W= upward force(thrust)

Therefore

[tex]W=3456 N[/tex]

Answer:

The total current in the circuit is 0.8 A.

Explanation:

internal resistance of each battery = 2 ohm

Total emf of the circuit, E = E1 + E2 = 2 = 2 = 4 V

Now total internal resistance is

[tex]r = \frac{2\times 2}{2 + 2}= 1 ohm[/tex]

Total resistance, R = 4 = 1 = 5 ohm

Let the current is I.

E = I R

4 = I x 5

I = 0.8 A

Answer:

7.3 g/cubic cm

Explanation:

You divide the mass by the volume to calculate the density of the metal.

146g ÷ 20cm³ = 7.3g/cm³

Answer: Symbol is I and unit A

Explanation: A represents Amperes

HOPE THIS HELPS!!!!!!!!

Answer:

yes,

Explanation:

because a compound contains two or more chemical elements chemically bond together.

Answer:

a = 1.375m/s²

Explanation:

F = m*a

55N = 40kg*a

a = 55N/40kg

a = 1.375m/s²

Answer:

B

Explanation:

Eff = output work/input work ×100

Hence, Eff = 10000/12000 × 100

Eff = 83.3%

The book's position is changing linearly with time, so its velocity is constant. This means that the net force acting on the book in the direction parallel to the surface is

∑ F = 10.0 N - n = 0

where n is the magnitude of the normal force on the book due to the wall, and the net force perpedicular to the surface is

∑ F = f - (0.550 kg) g = 0

where f is the mag. of kinetic friction, and f = µn where µ is the coefficient of kinetic friction.

Then

• n = 10.0 N

• f = (0.550 kg) g = 5.39 N

• 5.39 N = µ (10.0 N)

==>   µ = 0.539

Answer:

Above answer

Explanation:

The book's position is changing linearly with time, so its velocity is constant. This means that the net force acting on the book in the direction parallel to the surface is

∑ F = 10.0 N - n = 0

where n is the magnitude of the normal force on the book due to the wall, and the net force perpedicular to the surface is

∑ F = f - (0.550 kg) g = 0

where f is the mag. of kinetic friction, and f = µn where µ is the coefficient of kinetic friction.

Then

• n = 10.0 N

• f = (0.550 kg) g = 5.39 N

• 5.39 N = µ (10.0 N)

==>   µ = 0.539

Answer:

Liquid

Explanation:

In most liquids the particles are less densely packed giving them the ability to move around and slide past each other.

Answer:

The entropy change is 45.2 kJ/K.

Explanation:

mass of water at 100 C = 2 kg

Latent heat of vaporization, L = 2260 kJ/kg

Heat is

H = m L

H = 2 x 2260 = 4520 kJ

Entropy is given by

S = H/T = 4520/100 = 45.2 kJ/K

The entropy change during the phase change of water from liquids to steam at constant pressure and same temperatures will be zero because, Δ T is zero here.

Entropy is a thermodynamic parameter determining the measure of randomness in a system. Entropy of a natural reaction or change is always increasing.

According to second third law of thermodynamics the  entropy change of the universe is positive always. At constant pressure the entropy change a of substance of m g is written as:

ΔS = m Cp ln T2/T1.

Where Cp is the specific heat capacity at constant pressure.

Here, the initial temperature and final temperature is same 100 degree celsius. Thus T2/T1 becomes 1 and log 1 is zero. Therefore, the entropy  change in this phase change is zero.

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Answer:

when a two bodies A and B are moving at an angle 180° with each other then the relative velocity is the sum of bodies the velocity .i.e,

when the bodies move the opposite direction

then their relative velocity is the sum of individual velocities.

Answer:

Approximately [tex]5.19 \times 10^{-5}\; \rm N[/tex].

Explanation:

Let [tex]G[/tex] denote the gravitational constant. ([tex]G \approx 6.67 \times 10^{-11} \; \rm N \cdot kg^{-2} \cdot m^{2}[/tex].)

Let [tex]M[/tex] and [tex]m[/tex] denote the mass of two objects separated by [tex]r[/tex].

By Newton's Law of Universal Gravitation, the gravitational attraction between these two objects would measure:

[tex]\displaystyle F = \frac{G \cdot M \cdot m}{r^{2}}[/tex].

In this question: [tex]M = 7 \times 10^{22}\; \rm kg[/tex] is the mass of the moon, while [tex]m = 1\; \rm kg[/tex] is the mass of the water. The two are [tex]r = 3\times 10^{5}\; \rm km[/tex] apart from one another.

Important: convert the unit of [tex]r[/tex] to standard units (meters, not kilometers) to reflect the unit of the gravitational constant [tex]G[/tex].

[tex]\displaystyle r = 3 \times 10^{5}\; \rm km \times \frac{10^{3}\; \rm m}{1\; \rm km} = 3 \times 10^{8}\; \rm m[/tex].

[tex]\begin{aligned} F &= \frac{G \cdot M \cdot m}{r^{2}} \\ &= \frac{6.67 \times 10^{-11}\; \rm N \cdot kg^{-2}\cdot m^{2} \times 7 \times 10^{22}\; \rm kg \times 1\; \rm kg}{(3 \times 10^{8}\; \rm m)^{2}} \\ &\approx 5.19 \times 10^{-5} \; \rm N\end{aligned}[/tex].

Answer:

Explanation:

If the force of 2000 N is directed towards the right and the friction is directed towards the left, the 2000 N force is positive and the other is negative. To find the resultant force:

2000 - 500 = 1500 N to the right

Explanation:

Gravitational force depends upon the product of masses of the object. Earth has siginificantly greater mass than cricket ball. The product of masses for two ball is very low as compared to the product of earth and ball mass. That is why the gravitational force between earth and ball is relatively larger than two balls.

Answer:

The force of gravitation between the earth and the ball is large than the two balls.

Explanation:

The force of gravitation between the two bodies is directly proportional to the product of masses of two bodies and inversely proportional to the square of the distance between them.

So, when we take cricket balls , the masses of balls is very small and the distance is also small so the force between the two balls is small.

When we take earth and the ball, the mass of earth is very large eve distance is very large so the force between the earth and the ball is large as compared to the two balls.  

Answer:

Explanation:

The direction of the applied force has to be parallel to the distance an object moved in order to say that work has been done.

Answer:

climatic changes

ambient changes

human interferance and the growt of cities and human civilization

and invasive especies

Explanation:

Many different physical factors can impact the ecological tolerance of a species like:-

The portion of the abiotic factor's range of variation which a species can survive and function in is commonly defined as the tolerance range.

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Answer:

Explanation:

The formula for the electric field is

[tex]E=\frac{kQ}{r^2}[/tex]  where E is the magnitude of the electric field, k is Coulomb's constant, Q is the charge of the particle (which is NOT included in the formula), and r is the distance between the centers of the charges (for lack of a better description).

[tex]E=\frac{(9.0*10^9)*(6.5*10^{-6})}{(1.50)^2}[/tex] and we get, to 2 sig fig's

E = 2.6 × 10⁴ to the left (since electric fields are always pointing toward the negative charge and the electric field is to the right of the negative charge)

There are three things needed to be classified as a planet.

Pluto meets 2 of the 3.

The one it does not meet is it doesn’t “clear the neighborhood” which means a planet needs to be gravitationally dominant over all objects around it. Meaning smaller bodies ( asteroids) would either combine with the larger body making it bigger or pushing them away ( out of their orbit) so they do not collide with the larger body.

Answer:

D. A

General Formulas and Concepts:

Simple Harmonic Motion

Parts of a wave

Explanation:

The amplitude is the distance from the horizon to either the crest or trough of a wave.

In layman's terms, it is how high the wave is.

The "highest" wave would be wave A.

∴ our answer is D.

Topic: AP Physics 1 Algebra-Based

Unit: SMH

Answer:

A (The wave)

Explanation:

Wave A

Answer:

[tex]{ \bf{potential \: energy = mass \times gravitation \times height}} \\ 350 = 17 \times 10 \times h \\ 350 = 170h \\ height = 2.06 \: metres[/tex]