A body is thrown vertically upwards, remaining 4s in the air. Calculate the maximum height that the body reaches.

Answer:

Explanation:

Friction causes generation of heat and causes increased wear and tear.

The friction is a resistive force and is related to heat energy, so an increase in friction results in the generation of heat, so option D is correct.

Two solid objects cannot roll or slide over one another due to the force of friction. Although frictional forces can be useful, such as the traction needed to walk without slipping, they can also present a large degree of resistance to motion. Automobile engines need about 20% of their power to overcome frictional forces in moving parts.

The fundamental source of friction between metals appears to be the adhesion forces between the contact zones of the surfaces, which are always microscopically uneven. Friction is produced by shearing, these "welded" seams, and the rubbing action of the rougher, tougher surface against the softer, smoother surface.

The friction is a resistive force trying to oppose the force applied As friction is related to heat when we increase the heat, the friction increases, and vice versa.

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Answer:

e_{r} = Δa /a + Δd /Δ d + Δg / g

Explanation:

The error or uncertainty of a quantity is given by several factors, the most direct error is the absolute one that is given by the appreciation of the instruments, when some quantities obtained by a mathematical formula we must know how each error is programmed in the total error, we can see this with the relative error

the calculated quantity is Z

its relative error is

            [tex]e_{r}[/tex] = ΔZ/Z = 1/Z  (dZ /da Δa + dZ /dd Δd + dZ /dg Δg)

            e_{r} = 1 / Z (d /g  Δa + a /g  Δd + ad !1/g²! Δg)

            e_{r} = Δa /a + Δd /Δ d + Δg / g

notice that we take the worst case.

The measured quantities have absolute errors Da, Dd, Dg

Answer:

1.25x10^-19N

Explanation:see attached file pls

Answer:

2000 cm³

Explanation:

Assuming the pressure is constant:

V / T = V / T

1000 cm³ / 300 K = V / 600 K

V = 2000 cm³

Answer:

2.5 kg/m³

Explanation:

Absolute pressure = gauge pressure + atmospheric pressure

P = Pg + Pa

The gauge pressure caused by the weight of a fluid is called the static pressure.  It is equal to the density of the fluid × acceleration due to gravity × depth of the fluid,

Pg = ρgh

Therefore:

P = ρgh + Pa

300 Pa = ρ (10 m/s²) (8.00 m) + 100 Pa

ρ = 2.5 kg/m³

Answer:

A. 5.08 secs.

B. 10.16 secs.

C. 126.50 m.

D. 373.36 m

Explanation:

Data obtained from the question include the following:

Initial velocity (u) = 65 m/s

Angle of projection θ = 50°

A. Determination of the time taken to reach the peak.

Initial velocity (u) = 65 m/s

Angle of projection θ = 50°

Acceleration due to gravity (g) = 9.8 m/s²

Time (t) =.?

t = u•Sine θ/g

t = (65 × Sine 50) /9.8

t = 5.08 secs.

B. Determination of the total time spent by the ball in air.

Time (t) taken to reach the peak = 5.08 secs.

Total time (T) spent by the ball in air =?

T = 2t

T = 2 × 5.08

T = 10.16 secs

Therefore, the total time spent by the ball in air is 10.16 secs.

C. Determination of the maximum height.

Initial velocity (u) = 65 m/s

Angle of projection θ = 50°

Acceleration due to gravity (g) = 9.8 m/s²

Maximum height (H) =..?

H = u²•Sine² θ / 2g

H = 65² × (Sine 50)² / 2 × 9.8

H = 4225 × (Sine 50)² /19.6

H = 126.50 m

Therefore, the maximum height reached by the ball is 126.50 m.

D. Determination of the horizontal distance travelled by the ball.

Initial velocity (u) = 65 m/s

Angle of projection θ = 50°

Acceleration due to gravity (g) = 9.8 m/s²

Horizontal distance (R) =..?

R = u²•Sine 2θ / g

R = 65² × Sine (2×30) / 9.8

R = (4225 × Sine 60) / 9.8

R = 373.36 m

Therefore, the horizontal distance travelled by the ball is 373.36 m

Answer:

200 Watts.

Explanation:

Power is defines as the amount of work expended per unit time. Mathematically, it is expressed as Power = Workdone/Time

Given parameters

Energy used up 100Joules

Distance moved by brick = 1 meters

Time taken by the machine = 0.5 secs

Power can also be written as Energy/Time

Required

We need to calculate the amount of power used up.

Power = 100J/0.5s

Power = 100/(1/2)

Power = 100 * 2/1

Power = 200Watts.

This shows that the machine would expend 200Watts of power

Answer;

Motion: A body is said to be in motion if it changes its position with respect to its surroundings.

Explanation:

Rest and motion are the relative terms because they depend on the observer's frame of reference. So if two different observers are not at rest with respect to each other, then they too get different results when they observe the motion or rest of a body .

one example for each. Rest: If a body does not change its position with respect to its surroundings, the body is said to be at rest. ... Motion: A body is said to be in motion if it changes its position with respect to its surroundings.

Answer:

acceleration is the answer

Answer:

Acceleration

Explanation:

if it is horizontal line, that means position is same but time is increasing.

velocity=0 . particle is not even moving

Answer:

B. they have less mass than their reactants

Explanation:

In both nuclear fission and nuclear fusion, the products have less mass than their reactants. So, option B is correct.

Nuclear reaction is defined as the reaction that involves the collision between one or more atomic nuclei and a highly energetic subatomic particle to produce one or more nuclei along with the emission of a large amount of energy.

Here,

Nuclear fission and fusion are two types of nuclear reactions that involves the production of large amount of energy from atomic nuclei.

Nuclear fission is the nuclear reaction in which a heavier nucleus is split into two or more lighter nuclei, under radioactive condition, with the release of a massive amount of energy.

Nuclear fusion is the nuclear reaction in which two or more lighter nuclei nuclei fuse together under radioactive condition and forms a heavier nuclei and by releasing a large amount of energy.

In both nuclear fission and nuclear fusion, there occurs a release of large amount of energy. This is because most of the mass of the reactants is converted into energy which is known as the mass-energy. So the products of these nuclear reactions will have lesser mass than their reactants.

Hence,

In both nuclear fission and nuclear fusion, the products have less mass than their reactants.

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Answer:

Time seem to flow only in one direction because if it started to go in backward direction that would break the second law of thermodynamics. We do not find time to be moving in any direction because time is not an object that can move nor is it a force that can move any object.

Answer:

Explanation:

the resistance of a electrical device

R = V² / P where V is volt and P is power .

The devices are in parallel so same volt will apply on them

So R₁ = 12² / 32.5 = 4.431 ohm

R₂ = 12² / 2 x 10³ = .072 ohm

when they are in series

Common Current in them = 12 / 4.431 + .072

= 2.6649 A

power consumed by first device when they are in series

= current² x resistance

= 2.6649² x 4.431 = 31.46 W

power consumed by other

= 2.6649² x .072  = .511 W

Answer:

Explanation:

1. A parsec is defined as the distance from the Sun which would result in a parallax of_TWO____ arcsecond as seen from Earth when observed 6 months apart.

2. One parsecs is about_3.3____light years

3. The more distant a star, the_LESS ____its parallax.

4. The statement "we can measure stellar parallax for most stars in our galaxy" is__TRUE .___.

5. The closest stars have parallaxes smaller than_.002 _____arcsecond.

6. The first successful measurements of stellar parallax were made by_Friedrich Bessel_____in year_1838_____for the star named.

7. Star Fred has parallax four times greater than star Bob. Star Fred is__4____times_nearer_____than star Bob.

Answer:

if it's velocity u talking of.....

Explanation:

then it's displacement/ time

Answer:

Explanation:

We shall apply gas law formula to get the solution .

P₁ V₁ / T₁ = P₂ V₂ / T₂

P₁ = 10⁵ + 18 x 10³ x 9.8  where 10⁵ Pa is atmospheric  pressure at surface

= 1.764 x 10⁵ + 10⁵

= 2.764 x 10⁵

2.764 x 10⁵  x 3 / ( 273 + 9 ) = 10⁵ x V₂ / ( 273 + 22 )

V₂ = 8.67 cm³

Answer:

5.23 C

Explanation:

The current in the wire is given by I = ε/R where ε = induced emf in the wire and R = resistance of wire.

Now, ε = -ΔΦ/Δt where ΔΦ = change in magnetic flux = AΔB and A = area of loop and ΔB = change in magnetic field intensity = B₂ - B₁

B₁ = 0.670 T and B₂ = 0 T

ΔB = B₂ - B₁ = 0 - 0.670 T = - 0.670 T

A = πD²/4 where D = diameter of circular loop = 13.2 cm = 0.132 m

A = π(0.132 m)²/4 = 0.01368 m² = `1.368 × 10⁻² m²

ε = -ΔΦ/Δt = -AΔB/Δt = -1.368 × 10⁻² m² × (-0.670 T)/Δt= 0.9166 × 10⁻² Tm²/Δt

Now, the resistance R of the circular wire R = ρl/A' where ρ = resistivity of copper wire =  1.68 x 10⁻⁸ Ω.m, l = length of wire = πD and A' = cross-sectional area of wire = πd²/4 where d = diameter of wire = 2.25 mm = 2.25 × 10⁻³ m

R = ρl/A' = 1.68 x 10⁻⁸ Ω.m × π × 0.132 m÷π(2.25 × 10⁻³ m)²/4 = 0.88704/5.0625 = 0.1752 × 10⁻² Ω = 1.752 × 10⁻³ Ω

So, I = ε/R = 0.9166 × 10⁻² Tm²/Δt1.752 × 10⁻³ Ω  

IΔt = 0.9166 × 10⁻² Tm²/1.752 × 10⁻³ Ω = 0.5232 × 10 C

Since ΔQ = It = 5.232 C ≅ 5.23 C

So the charge is 5.23 C

The induced emf through wire depends on the current flow (indirectly with charge flow as well).

The value of charge moving past a point in the coil during its operations is 5.23 C.

The region in a space where a particle experiences some magnetic force, is known as the magnetic field.

Given data -

The diameter of the circular loop is, d = 13.2 cm = 0.132 m.

The change in magnetic field strength is, ΔB = 0.670 T.

The new diameter of the wire is, d' = 2.25 mm = 2.25 × 10³ m.

The resistivity of the wire is, [tex]\rho = 1.68 \times 10^{-8} \;\rm \Omega.m[/tex].

The current in the wire is given by the following expression,

I = ε/R

Here,

ε is the induced emf in the wire.

R is the resistance of the wire.

And the expression for the induced emf of the wire is given as,

ε = -ΔΦ/Δt

Here,

ΔΦ is the change in magnetic flux. And its expression is,

ε = A × ΔB

Here,

A is the area of the loop. And its value is, A = πd²/4.

Solving as,

A = π(0.132 m)²/4

A = 0.01368 m²
A = `1.368 × 10⁻² m²

Now, calculating the induced emf as,

ε = ΔΦ/Δt

ε = A × ΔB/Δt

ε = 1.368 × 10⁻² m² × (0.670 T)/Δt

ε = 0.9166 × 10⁻² Tm²/Δt

Now, the resistance R of the circular wire is,

R = ρ × L/A'

Here,

L is the length of the wire and its value is. L = πd .

And A' is the new cross-sectional area of wire,

A' = πd'²/4

So, the resistance is,

R = ρ × L/A'

R = 1.68 x 10⁻⁸  ×( π × 0.132 m) ÷ π(2.25 × 10⁻³ m)²/4 =

R = 0.88704/5.0625

R = 0.1752 × 10⁻² Ω

R = 1.752 × 10⁻³ Ω

Now, the current flow (I) in the wire is given as,

I = ε/R

I = 0.9166 × 10⁻² Tm²/Δt1.752 × 10⁻³ Ω  

And obtaining the value of charge from the expression of current as,

Q = IΔt
Q = 0.9166 × 10⁻² Tm²/1.752 × 10⁻³ Ω

Q = 0.5232 × 10 C

Q = 5.23 C

Thus, we can conclude that the value of charge moving past a point in the coil during its operations is 5.23 C.

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Answer:

D. AC+BD -> AD +BC

Explanation:

I got it right

A double displacement reaction is also called the double replacement reaction or double decomposition reaction. Here AC + BD → AD + BC is a double displacement reaction. The correct option is D.

A double displacement reaction is defined as a chemical reaction in which the positive and negative ions of two ionic compounds exchange their places to form two new compounds. The general form of a double displacement reaction is given as:

AC + BD → AD + BC

Here 'A' and 'B' are positively charged cations, whereas 'C' and 'D' are negatively charged anions. The double displacement reactions generally occur between the substances in an aqueous solution. In order for a reaction to occur, one of the products is usually a solid precipitate, a gas or a molecular compound like water.

Thus the correct option is D.

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Answer:

59%

Explanation:

Data obtained from the question include the following:

Input temperature = 495 K

Output temperature = 293 K

Efficiency =?

The efficiency of the car engine can be obtained by multiplying the ratio of the output temperature to the input temperature by 100 as shown below:

Efficiency = output /input x 100

Efficiency = 293/495 x 100

Efficiency = 59.1 ≈ 59%

Therefore, the efficiency of the car engine is approximately 59%

Answer:

Flexibility Increases

Pre-breathe time decreases

Mass of suit decreases.

Explanation:

Spacesuits are designed for space shuttles when a person goes to explore the galaxy. The spacesuits shuttle era are pressurized at 4.3 pounds per inch. The gas in the suit is 100% of oxygen and there is more oxygen to breathe when the altitude of 10,000 is reached. This will decrease the breathing time and mass of suit.

Answer:

The magnitude and direction of the force per unit length of one wire on the other is 2 x 10⁻⁵ N/m, attractive force.

Explanation:

Given;

distance between the two parallel wires, r = 10 cm = 0.1 m

current in the first wire, I₁ = 2A

current in the second wire, I₂ = 5 A

The force per unit length on each wire can be calculated as;

[tex]\frac{F}{L} = \frac{\mu_oI_1I_2}{2\pi r}[/tex]

where;

μ₀ is permeability of free space = 4π x 10⁻⁷ m/A

[tex]\frac{F}{L} = \frac{\mu_oI_1I_2}{2\pi r} \\\\\frac{F}{L} = \frac{4\pi*10^{-7}*2*5}{2\pi *0.1} \\\\\frac{F}{L} = 2 *10^{-5} \ N[/tex]/ m

The direction of the force between the two wires is attractive since the current in the two wires are in opposite direction.

Therefore, the magnitude and direction of the force per unit length of one wire on the other is 2 x 10⁻⁵ N/m, attractive force.

Answer:

1.) 440 Hz

2.) 659.3 Hz

Explanation:

1.) Given parameters are:

wavelength = 0.77955 m.

speed of sound = 343.00 m/s

Frequency = speed/ wavelength

Substitute speed and wavelength into the formula

Frequency = 343/ 0.77955

Frequency = 439.99

Frequency = 440 Hz approximately

2.) The parameters given are:

wavelength = 0.52028 m.

speed of sound = 343.00 m/s

Using the same formula

Frequency = speed/wavelength

Substitute all the parameters into the formula

Frequency = 343 / 0.52028

Frequency = 659.3 Hz approximately

The pitch of a note depends on the frequency of the sound waves.

The pitch of a sound increases as the frequency of the sound waves increases.

Answer:

1.) 440 Hz

2.) 659.3 Hz

Explanation:

1.) Given parameters are:

wavelength = 0.77955 m.

speed of sound = 343.00 m/s

Frequency = speed/ wavelength

Substitute speed and wavelength into the formula

Frequency = 343/ 0.77955

Frequency = 439.99

Frequency = 440 Hz approximately

2.) The parameters given are:

wavelength = 0.52028 m.

speed of sound = 343.00 m/s

Using the same formula

Frequency = speed/wavelength

Substitute all the parameters into the formula

Frequency = 343 / 0.52028

Frequency = 659.3 Hz approximately

The pitch of a note depends on the frequency of the sound waves.

The pitch of a sound increases as the frequency of the sound waves increases.

Answer:

yeah this statement is tru

Explanation:

it is because the speed of the bullet is more than the speed of rolling ball .so from this reason we cannot catch a bullet.

A bullet will be moving much faster than a rolling ball. Even seeing a bullet in flight requires it to be extremely low velocity.

Explanation:

Power = work / time

Power = force × distance / time

P = (650 kg) (10 m/s²) (20 m) / (15 s)

P = 8667 W

Answer:D

Explanation:

Apex

Answer:

a)  v = 2.21 10⁷ m / s, b)  B = 6.04 10⁻⁴ T , c)  f = 1.69 10⁷ Hz , d)     T = 5.9 10⁻⁸ s

Explanation:

a) For this exercise, let's start by using the concept of kinetic energy

           K = ½ m v²

           v = √ 2K / m

Let's reduce the magnitudes to SI units

          E = K = 1.39 kev (1000 eV / 1 keV) (1.6 10⁻¹⁹ J / 1 eV) = 2,224 10⁻¹⁶ J

          r = 20.8 cm (1 m / 100 cm) = 0.208 m

let's calculate

          v = √ (2 2,224 10⁻¹⁶ / 9.1 10⁻³¹)

          v = √ (4.8879 10¹⁴)

          v = 2.21 10⁷ m / s

b) let's use Newton's second law where the force is magnetic

              F = m a

where the acceleration is centripetal

              a = v² / r

the magnetic force is

              Fm = q v x B = q v B sin θ

since the circle is perpendicular to the magnetic field, the angle is 90º and the sine is equal to one, let's substitute

          qv B = m v² / r

          B = m v / rq

let's calculate

          B = 9.1 10⁻³¹ 2.21 10⁷ / (0.208  1.6 10⁻¹⁹)

          B = 6.04 10⁻⁴ T

c) Linear and angular variables are related

          v = w r

          w = v / r

          w = 2.21 10⁷ / 0.208

          w = 1.0625 10⁸ ras / s

    angular velocity and frequency are related

          w = 2π f

          f = w / 2π

          f = 1.0625 10⁸ / (2π)

          f = 1.69 10⁷ Hz

d) the frequency is the inverse of the period

          f = 1 / T

          T = 1 / 1.69 10⁷

           T = 5.9 10⁻⁸ s

Answer:

The deviation of a mirror is equal to twice the angle of incidence.The total angle between the straight-line path and the reflected ray is twice the angle of incidence. This is called the deviation of the light and measures the angle at which the light has strayed from its initial straight-line path.

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Answer:

2 hrs

Explanation:

time = distance ÷ speed

Answer:

The solenoid has 213 turns.

Explanation:

The number of the solenoid's turns (N) can be found as follows:

[tex] N = \frac{L*I}{\phi_{B}} [/tex]    (1)

Where:

L: is the self-inductance of the solenoid

I: is the current = 1.40 A

[tex]\phi_{B}[/tex]: is the magnetic flux = 0.00308 Wb      

The self-inductance of the solenoid (L) is:

[tex] L = \frac{|\epsilon|}{|dI/dt|} [/tex]   (2)

Where:

ε: is the induced emf = 12.2x10⁻³ V

dI/dt: is the rate changing of the current = 0.0260 A/s

By entering equation (2) into (1) we can find the number of turns:

[tex] N = \frac{|\epsilon|*I}{\phi_{B}|dI/dt|} = \frac{12.2 \cdot 10^{-3} V*1.40 A}{0.00308 Wb*0.0260 A/s} = 213 [/tex]        

Therefore, the solenoid has 213 turns.

I hope it helps you!

Answer:

The answer is B.

Explanation:

Given that the current (Ampere) in a series circuit is same so we can ignore it. We can assume that the total voltage is 60V and all the 3 resistance are different, 20Ω, 40Ω and 60Ω. So first, we have to find the total resistance by adding :

Total resistance = 20Ω + 40Ω + 60Ω

= 120Ω

Next, we have to find out that 1Ω is equal to how many voltage by dividing :

120Ω = 60V

1Ω = 60V ÷ 120

1Ω = 0.5V

Lastly, we have to calculate the voltage at R1 so we have to multiply by 20 (R1) :

1Ω = 0.5V

20Ω = 0.5V × 20

20Ω = 10V