HURRY What happened when the speed was increased?

Answer:

f" = 40779.61 Hz

Explanation:

From the question, we see that the bat is the source of the sound wave and is initially at rest and the object is in motion as the observer, thus;

from the Doppler effect equation, we can calculate the initial observed frequency as:

f' = f(1 - (v_o/v))

We are given;

f = 46.2 kHz = 46200 Hz

v_o = 21.8 m/s

v is speed of sound = 343 m/s

Thus;

f' = 46200(1 - (21/343))

f' = 43371.4285 Hz

In the second stage, we see that the bat is now a stationary observer while the object is now the moving source;

Thus, from doppler effect again but this time with the source going away from the obsever, the new observed frequency is;

f" = f'/(1 + (v_o/v))

f" = 43371.4285/(1 + (21.8/343))

f" = 40779.61 Hz

Answer:

30 degrees

Explanation: reflection, same angle

For a ray of monochromatic light is incident on a plane mirror at and angle of 30°. The angle of reflection for the light is 30°.

Reflection occurs when radiation bounces off from a surface. Light is an electromagnetic wave and it can be reflected. According to the laws of reflection, the angle of incidence is equal to the law of reflection.

Hence, for a ray of monochromatic light is incident on a plane mirror at and angle of 30°. The angle of reflection for the light is 30°.

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Answer: black

Explanation: When green light is shone on a red object, it absorbs all of the green light and not reflecting anything. Hence, it appears black.

Answer:

Explanation:

The capacitor is of parallel plate capacitor type

Capacitance C = ε₀ A / 4π d

ε₀  is 8.85 x 10⁻¹² , A  is plate area and  d is distance between plate .

d = 1.7 cm

C = 8.85 x 10⁻¹² x π x (6.5 x 10⁻² )² / 4π x 1.7 x 10⁻²

= 55 x 10⁻¹⁴F .

Charge on each electrode = C x V , V is voltage of battery .

= 55 x 10⁻¹⁴ x 14

= 770 x 10⁻¹⁴ C  

Electric field strength = V / d where V is potential difference of battery , d is distance between plate .

= 14 / 1.7 x 10⁻²

= 8.23 x 10² V / m

The potential difference between plate

= potential difference of the battery

= 14 V .

Answer:

its b for sure

Explanation:

Answer:

B. It might be accessed by someone who was not the intended

recipient

Answer:

b. U = Q - W

Explanation:

Given;

change in internal energy, ΔU = 36 kJ

heat transferred to the surroundings Q  = 14 kJ

Apply first law of thermodynamic; the change in internal energy is equal to heat added to the system minus work done by the system.

ΔU = Q - W

Since heat was lost to surroundings, Q = - Q

ΔU = (-Q) - W

36 kJ = -14 kJ - W

36 kJ + 14 kJ = - W

50 kJ = - W

W = - 50 kJ (the negative sign shows that work has been done on the system)

Thus, 50 kJ of work is done on the system.

The only correct answer in the given options is "b" U = Q-W

Answer:

1796.48 m

Explanation:

Given that :

First part of journey :

Initial Velocity, u = 0

Acceleration, a, = 1.60 m/s²

Time, t = 14 s

Distance traveled, S = 0.5at²

S = 0.5 * 1.60 * 14²

S1 = 156.8m

2nd part :

Speed is constant

Time = 70 seconds

At constant speed ;

Distance = speed * time

Speed, V = u + at

V = 0 + 1.6*14

V = 22.4 m/s

Distance, S2 = 22.4 * 70 = 1568 m

3rd part :

Deceleration = - 3.50m/s²

Final velocity, v = 0

Time taken to attain rest

V = u + at

0 = 22.4 - 3.5(t)

3.5t = 22.4

t = 22.4/3.5

t = 6.4 seconds

S3 = ut - 0.5at² (deceleration)

S3 = (22.4*6.4) - 0.5(3.5)*6.4^2

S3 = 71.68m

S1 + S2 + S3

156.8m + 1568m + 71.68m

= 1796.48 m

Answer:

Explanation:

Let t represent the time for Tina to catch David.

Hence, considering the equation of linear motion S = ut + 1/2at^2..... 1

For David u = 28.0 m/s where 'a' is set to nought

S = ut

S = 28t.......2

For Tina consider equation 1

Where acceleration = 2.90m/s^2 and u is set at nought

S = 1/2×2.90 m/s×t^2.......3

Equate 2 and 3

28t = 1.45t^2

Divide through by t

28 = 1.45t

t = 28/1.45

t = 19.31seconds

Now put the value of t into equation 3

S = 1/2×2.90 m/s×t^2.......3

= 1.45×20×20

= 580m

Tina must have driven 580meters before passing David

Considering the equation of linear motion : V^2 = U^2+2as

Where u is set at nought

V^2 = 2as

V^2 = 2×2.9×580

V^2 = 3364

V = √3364

V = 58m/s

Her speed will be 58m/s

(a) Tina should drive for 580 m, before passing the David.

(b) The speed of Tina during her passage through the David is 58 m/s.

Given data:

The initial velocity of the David is, u = 28.0 m/s.

The magnitude of acceleration is, [tex]a = 2.90 \;\rm m/s^{2}[/tex].

(a)

We can use the second kinematic equations of motion to obtain the distance covered by Tina, before passing the David. As per the second kinematic equation of motion,

[tex]s= u't + \dfrac{1}{2}at^{2}[/tex]

Here, u' is the initial speed of Tina and t is the time interval. Then,

Let t represent the time for Tina to catch David.

Hence, considering the equation of linear motion as,

S = ut + 1/2at²...............................................................(1)

Also,

S = ut

S = 28t ...........................................................................(2)

For Tina consider equation 1

S = 1/2×2.90t²................................................................(3)

Equate 2 and 3

28t = 1.45t²

 28 = 1.45t

t = 28/1.45

t = 19.31 seconds

Now put the value of t into equation (3)

S = 1/2×2.90 t².

   = 1.45×20×20

   = 580m

Thus, we can conclude that Tina should drive for 580 m, before passing the David.

(b)

Now, using the third kinematic equation of motion to obtain the speed of Tina during her passage through David as,

v² = u²+2as

Solving as,

v² = 28.0² + 2(2.90)(580)

v = √3364

v = 58m/s

Thus, we can conclude that the speed of Tina during her passage through the David is 58 m/s.

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Answer:

10. 65 N

11. 35 N

Explanation:

10. Determination the force that sends the soccer ball towards the goal.

We'll begin by calculating the acceleration of the ball. This can be obtained as follow:

Initial velocity (u) of the ball = 0 m/s

Final velocity (v) of the ball = 32.5m/s time (t) = 0.21 s

Acceleration (a) of the ball =?

a = (v – u) /t

a = (32.5 – 0) / 0.21

a = 32.5 / 0.21

a = 154.76 m/s²

Finally, we shall determine the force that sends the soccer ball towards the goal. This can be obtained as follow:

Mass (m) of the ball = 0.42 kg

Acceleration (a) of the ball = 154.76 m/s²

Force (F) =?

F = ma

F = 0.42 × 154.76

F = 65 N

Thus, the force that sends soccer ball towards the goal is 65 N

11. Determination of the force exerted by the rocket on the satellite.

We'll begin by calculating the acceleration of the satellite. This can be obtained as follow:

Initial velocity (u) of satellite = 0 m/s

Final velocity (v) of satellite = 0.63 m/s

Time (t) = 1296 s

Acceleration (a) of the satellite =?

a = (v – u) /t

a = (0.63 – 0) / 1296

a = 0.63 / 1296

a = 4.861×10¯⁴ m/s²

Finally, we shall determine the force exerted by the rocket on the satellite. This can be obtained as follow:

Mass (m) of the satellite = 72000 Kg

Acceleration (a) of the satellite = 4.861×10¯⁴ m/s²

Force (F) =?

F = ma

F = 72000 × 4.861×10¯⁴

F = 35 N

Thus, the force exerted by the rocket on the satellite is 35 N

Answer:

a)   d = 12 km, d = 0,  b)  v = 0.4 km / min, v = 0,  c) v = 0

Explanation:

This problem asks to find the distance and the displacement. We must emphasize that the distance is a scalar and the displacement is a vector quantity

In the exercise, the bold letters indicate vectors

a) Let's find the total distance of the trip

           d = d₁ + d₂

where d₁ is the distance to get to the flowers and d₂ is the distance to return to the hive from the flowers

             d₁ = d₂ = 6 km

             d = 12 km

we look for the displacement that is a vector quantity

          d = d₁ - d₂

since the second displacement is in the opposite direction of the first

          d = 0

b) the average speed of the trip, again this magnitude is a scalar

          v = d / t

distance is d = 12 km t total time is t = 15 + 15 = 30 min

          v = 12/30

          v = 0.4 km / min

average velocity (vector) of the entire travel, in that case the displacement is zero

          v = 0

c) If the path is not a straight line but the time is the same, the average speed cannot be calculated since it lacks the distance value

In the same case to calculate the average velocity that is a vector, it will be zero since the net displacement is zero

            v = 0

Answer:

B

Explanation:

8-2 is 6

times that times 8 u get B

Answer:

CuCl₂   +    H₂S    →    CuS   +    2HCl  

Explanation:

The unbalanced reaction expression is given as;

        CuCl₂   +    H₂S    →    CuS   +    HCl

The problem here involves balancing of chemical equations.

 We use a mathematical approach to solve this problem. Here assign coefficients a, b, c and d as values that will effect the balance;

          aCuCl₂   +    bH₂S    →    cCuS   +    dHCl

Conserving Cu:  a  = c

                     Cl:   2a  = d

                     H: 2b  = d

                     S: b  = c

let a  = 1; c  = 1, b  = 1 and d  = 2

         CuCl₂   +    H₂S    →    CuS   +    2HCl  

Explanation:

Elements are distinct substances that cannot be split-up into simpler substances. These substances consist of only one kind of atom.

There are over one hundred elements known to date. Each of these elements is usually symbolized by a capital letter or a capital letter followed by a small letter derived from English or Latin or Greek name of the element concerned.

Elements can be categorized in different ways.

Atoms are the smallest unit of elements that takes part in a chemical reaction.

Explanation:

From the experiment:

      Number of protons  = 74

      Number of neutrons  = 110

Number of protons in an element is the atomic number of the element. It is used to locate and position and element on the periodic table.

For a neutral or uncharged atom, the number of protons is the same as the number of electrons.

The element whose number of protons or atomic number if 74 is Tungsten

  Mass number  = 74 + 110  = 184g/mol

Answer:  momentum is determined and conserved.

Answer:

monument is determined

Answer:

1.704 × 10¹⁹ electrons

Explanation:

The gravitational force due to the identical masses with mass, m = 3.17 kg at a distance r = 2.96 m from each other is F = Gm²/r².

Since equal number of electrons have to leave both masses, we have a charge q on each mass acting to oppose each other at distance r.

So, the electrical force of repulsion is thus

F'= kq²/r²

For the net force to be zero, the gravitational force of attraction must balance the electrical force of repulsion.

So, F = F'

So,  Gm²/r² = kq²/r²

Gm² = kq²

q² = Gm²/k

taking square root of both sides, we have

q = m√(G/k)

So, substituting the values of the variables into the equation, we have

q = m√(G/k)

= 3.17 kg√(6.67 × 10⁻¹¹ Nm²/kg²/9 × 10⁹ Nm²/C²)

= 3.17 kg√(0.741  × 10⁻²⁰ C²/kg²)

= 3.17 kg × 0.861 C/kg

= 2.73 C

Now, q = ne where n = number of electrons and e = electron charge = 1.602 × 10⁻¹⁹ C

n = q/e

= 2.73 C ÷ 1.602 × 10⁻¹⁹ C

= 1.704 × 10¹⁹ electrons

Answer:

The ice will melt

Heat flows from the water to the ice

Explanation:

If we add a lump of ice to a tumbler containing water, the ice lump will melt in the water.

This is a simple physical change of state from solid to liquid.

At the end both the solid ice and the original liquid maintains the liquid state.

Answer:

F = 0.78[N]

Explanation:

The given values correspond to forces, we must remember or take into account that the forces are vector quantities, that is, they have magnitude and direction. Since we have two X-Y coordinate axes (two-dimensional), we are going to decompose each of the forces into the X & y components.

For F₁

[tex]F_{y}=2[N][/tex]

For F₂

[tex]F_{x}=2*cos(60)\\F_{x}=1[N]\\F_{y}=-2*sin(60)\\F_{y}=-1.73[N][/tex]

For F₃

[tex]F_{x}=-1*sin(60)\\F_{x}=-0.866[N]\\F_{y}=1*cos(60)\\F_{y}=0.5 [N][/tex]

Now we can sum each one of the forces in the given axes:

[tex]F_{x}=1-0.866=0.134[N]\\F_{y}=2-1.73+0.5\\F_{y}=0.77[N][/tex]

Now using the Pythagorean theorem we can find the total force.

[tex]F=\sqrt{(0.134)^{2} +(0.77)^{2}}\\F= 0.78[N][/tex]

Answer: The focal length of the lens = 3.32 cm.

Explanation:

Lens formula : [tex]\dfrac1f=\dfrac1v-\dfrac1u[/tex]    (i)

f= focal length , v=image distance , u =object distance.

magnification: m = [tex]\dfrac{v}{u}[/tex]   (ii )

Given: v= -12.8 cm , m =2.85

Put values in (ii), we get

[tex]2.85=\dfrac{-12.8}{u}\\\\\Rightarrow\ u=\dfrac{-12.8}{2.85}\\\\\Rightarrow\ u=-4.49\ cm[/tex]

substitute values of u , v in (i)

[tex]\dfrac1f=\dfrac1{-12.8}-\dfrac{1}{4.49}\\\\\Rightarrow\dfrac1f=-0.30084214922\\\\\Rightarrow\ f=\dfrac{-1}{-0.30084214922}\approx3.32\ cm[/tex]

Hence, the focal length of the lens = 3.32 cm.

Answer:

6.92

Explanation:

2.85=-(-12.8/x)

do=4.49

1/f= 1/4.49 + 1/-12.8

f=6.92

Answer:

a) θ = 58.3º

b) vfh = 13.7 m/s

c) g = -9.8 m/s2

d) h = 22.2 m

e) vfb = 15.5 m/s

Explanation:

a)

        [tex]x_{f} = v_{ox} * t = v_{o} * cos \theta * t (2)[/tex]

        [tex]cos \theta = \frac{x_{f} }{v*t} = \frac{41.0m}{26.0m/s*3.00s} = 0.526 (3)[/tex]

b)

c)

d)

       [tex]\Delta y = v_{oy} * t - \frac{1}{2} *g*t^{2} (6)[/tex]

       [tex]\Delta y = 22.1 m/s* 3.0s - \frac{1}{2} *9.8m/s2*(3.00s)^{2} = 22.2 m (8)[/tex]

e)

       [tex]v_{fy} = v_{oy} - g*t (9)[/tex]

       [tex]v_{fy} = 22.1 m/s - 9.8m/s2*3.00s = -7.3 m/s (10)[/tex]

       [tex]v_{f} = \sqrt{(13.7m/s)^{2} +(-7.3m/s)^{2}} = 15.5 m/s (11)[/tex]

Answer:

The period of the swing depends on only the length of the string and not on the mass of the bob and the period of the pendulum depends on only the horizontal component of g.

Explanation:

The period of the swing depends on only the length of the string and not on the mass of the bob. Since the length of the string and the mass of the bob define the pendulum.

Also, the properties that define the motion are the component of the weight of the bob in the horizontal direction which determines the to and fro movement of the bob. So, the period of the pendulum depends on only the horizontal component of g.

So, T = 2π√(l/g) where l = length of pendulum and g = acceleration due to gravity.

Explanation:

Every object has a center of gravity. ... The force of gravity acting on an object is directed through this center of gravity and toward the center of the earth. The object's weight, W, can be represented by a vector directed down (along the line the object would fall if it were dropped).

It should be towards the center of the earth.

The following information should be considered:

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Answer:

The answer is I

Explanation:

Answer:

4.) l, ll, and lll only

Explanation:

The rest of the answers:

1.) The field energy will increase.

2.) The energy increases, and the lines of force are denser.

3.) It points toward the field of earths magnetic poles.

5.) ll, lV, l, lll

Answer:

B.

Explanation:

From the given information, since the capacitors are disconnected from the battery, the electric field between the plate does not change due to the fact that there is no difference in charge density.

Hence, the potential difference after separating the plates is:

V' = Ed

V = e (2d')

V' = 2V

For the energy stored in the capacitor;

[tex]U' = \dfrac{1}{2}QV'[/tex]

where;

V' = 2V

[tex]U' = \dfrac{1}{2} Q (2V)}[/tex]

[tex]U' =2( \dfrac{1}{2} Q V)[/tex]

U' = 2U

Thus, in the capacitor, the energy that is being stored is doubled.

Answer:

20 J

Explanation:

Work done is given force by distance .

W= F * d  where F is force given by the product of pressure and area

W= P* Δv  where Δv  is change in volume.

Given that ;

1 mole of an ideal gas is kept at 0°C, the pressure of the gas is : 1 atm.

Δv  is change in volume , 30 l - 10l = 20 l

W= 1 * 20 = 20 J

Answer:

3. The frequency of the wave is 3 Hz.

Explanation:

3. Determination of the frequency of the wave.

Frequency is simply defined as the number of complete circle or oscillation made in 1 seconds. Mathematically, it can be expressed as:

f = n / t

Where:

f => is the frequency.

n => is the number of circle.

t => is the time.

With the above formula, we can obtain the frequency of the wave as follow:

Number of complete circle (n) = 3

Time (t) = 1 s

Frequency (f) =?

f = n / t

f = 3 / 1

f = 3 /s = 3 Hz

Therefore, the frequency of the wave is 3 Hz

Answer:

15448

Explanation:

A=11000(1.01425)^{24}

A=11000(1.01425)  

24

Austin invested $11,000 in an account paying an interest rate of 5.7% compounded quarterly. Assuming no deposits or withdrawals are made, the money to the nearest dollar, would be in the account after 6 years is 15448.

The compound interest occurs when the interest is reinvested rather than paying it out. It's basically earning interest over interest.

The formula is:

Compound interest, [tex]A = P ( 1 +\frac{r}{n} )^{nt}[/tex]

Where:

A = final Amount

P = initial principal balance

r = interest rate

n = number of times interest applied per time period

t = number of time periods elapsed

Austin invested P=$11000 in an account with an interest rate of r=5.7% = 0.057 (decimal) during t=6 years compounded quarterly. Since there are 4 quarters in a year, n=4.

Thus, Substituting all the values in the given formula,

A = 11000 ( 1 + [tex]\frac{0.057}{4} )^{6*4}[/tex]

 = 11000 × 1.4043662796

 = 15448.0290

The money to the nearest dollar, would be in the account after 6 years is 15448.

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#SPJ2

Answer:

Emec = 94050 [J]

Explanation:

In order to solve this problem, we must understand that all thermal energy is converted into mechanical energy.

The thermal energy can be calculated by means of the following expression.

[tex]Q=m*C_{p}*(T_{final}-T_{initial})[/tex]

where:

Q = heat [J]

Cp = specific heat of water = 4186 [J/kg*°C]

m = mass = 300 [g] = 0.3 [kg]

T_final = 95 [°C]

T_initial = 20 [°C]

Now we can calculate the heat, replacing the given values:

[tex]Q=0.3*4180*(95-20)\\Q= 94050[J][/tex]

Since all this energy must come from the mechanical energy delivered by the exercise bike, and no energy is lost during the process, the mechanical energy must be equal to the thermal energy.

[tex]Q=E_{mec}\\E_{mec}=94050[J][/tex]

Answer:

Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi), and one complete orbit takes 365.256 days (1 sidereal year), during which time Earth has traveled 940 million km (584 million mi).

Explanation: