A student sits on a rotating stool holding two 1 kg objects. When his arms are extended horizontally, the objects are 0.9 m from the axis of rotation, and he rotates with angular speed of 0.76 rad/sec. The moment of inertia of the student plus the stool is 5 kg m2 and is assumed to be constant. The student then pulls the objects horizontally to a radius 0.33 m from the rotation axis.

Required:
a. Find the new angular speed of the student.
b. Find the kinetic energy of the student before and after the objects are pulled in.

Answer:

ω = 0.571 rad/s

Explanation:

given data

radius = 30 m

solution

we take here g = 9.8 m/s²

and g is express as

g = r × ω²     ....................1

put here value and we get

9.8 = 30 × ω²

solve it we get

ω = 0.571 rad/s

Answer:

Explanation:

Angle of incidence at the longer face = 45⁰ ( see the figure in the attached file )

For total reflection from longer face

i = C where C is critical angle .

And relation between critical angle and refractive index is as follows .

μ = 1 / sinC

= 1 / sin45

= √2

= 1.414 .

Answer:

i Believe the correct answer is "An open circuit being changed into a closed circuit"

Explanation:

HERE IS YOUR ANSWER!

Answer:

c heats up cancer cells and weakens them.

Answer:

I think it is C

Explanation:

because

Answer:

a) 36°

b) 0.109 kg

Explanation:

Heat flows from brass to copper with the brass having its temperature

Length of brass = 0.4

Length of copper = 0.8

Temperature of = 36.15

See attachment for calculation

The temperature at the joint is 36.15°C

The amount of ice melted is 1.086 kg

The rate of transfer of thermal energy,

   H = Q/t = KAΔT/L

  where, K is the thermal conductivity of the substance, A is cross-sectional area, ΔT is temperature difference at the ends and L is the length

As given in the question,

  the length of the brass section   [tex]L_{1}[/tex] = 0.4 m

  it's thermal conductivity      [tex]K_{b}[/tex] = 109 J[tex]s^{-1}m^{-1}K^{-1}[/tex]

  the temperature at the brass end  [tex]T_{1}[/tex] = 373K

  the length of the copper section [tex]L_{2}[/tex] = 0.8 m

  it's thermal conductivity      [tex]K_{c}[/tex] = 385 J[tex]s^{-1}m^{-1}K^{-1}[/tex]

  the temperature at the brass end  [tex]T_{1}[/tex] = 273K

 cross-sectional area of both the substance is same A = 0.007 [tex]m^{2}[/tex]

  Let the temperature at the joint be T

The rate of heat flow must be constant across the whole length of the setup.

Hence at the joint,

   [tex]\frac{K_{b}A(T_{1}-T) }{L_{1} } =\frac{K_{c}A(T-T_{2}) }{L_{2} }[/tex]

⇒ [tex]\frac{ 109*A*(373-T)}{0.4} =\frac{385*A(T-273)}{0.8}[/tex] ⇒ T=309.15 K

⇒ T = 36.15°C is the temperature at the joint.

Now we have to calculate the equivalent thermal conductivity K of the setup in order to calculate the amount of heat transfer.

considering equivalent thermal conductivity K throughout the setup we can form the following equation to calculate its value

   [tex]\frac{KA(T_{1}-T_{2} ) }{L_{1}+L_{2} } =\frac{K_{c}A(T-T_{2}) }{L_{2} }[/tex]

   ⇒   [tex]\frac{ K*A*(100)}{1.2} =\frac{385*A(36.15)}{0.8}[/tex]

   ⇒  K = 208.76 J[tex]s^{-1}m^{-1}K^{-1}[/tex]

the amount of heat transferred at the copper end in ice-water mixture in 5 minutes(300 seconds) :

        Q = [tex]\frac{KA(T_{1}-T_{2} ) }{L_{1}+L_{2} }[/tex] × t =  [tex]\frac{208.76*0.007*100}{1.2}[/tex] × 300 = 36533 J

        latent heat of fusion of ice [tex]L_{f}[/tex] = 33600 J/kg

         [tex]Q=mL_{f}[/tex]

         [tex]m=\frac{Q}{L_{f} }[/tex]

         [tex]m=\frac{36533}{33600}[/tex] ⇒ m = 1.086 kg of ice is melted in 5 minutes

Learn more about heat transfer:

https://brainly.com/question/20725399?referrer=searchResults

Answer:

21 hours

Explanation:

well 30 x 20 = 600 than 21 = 630

Answer:

a) a = - 1.76 m / s²,  b)   F = 20.5 N, c)  w = 3.55 rad / s

Explanation:

a) a simple harmonic motion is described by the expression

          x = A cos (wt + Ф)

in this case they give us the frequency

         w = 2π f

         w = 2π 0.40

         w = 2.51 rad / s

as the maximum elongation is 0.65 m this corresponds to the amplitude of the movement

         A = 0.65 m

to find the phase constant (Ф) we use the initial condition that for t = 0 v = 0 and x = A, we substitute

          A = A cos (0+ Ф)

         cos Ф = 1

         Ф = 0

the resulting equation is

         x = 0.65 cos (2.51 t)

Let's find the time it takes to get to x = 0.28 m

         0.28 = 0.65 cos 2.51 t

          2.51 t = cos-1 (0.28 / 0.65)

remember angles are in radians

          t = 1.1254 / 2.51

          t = 0.448 s

the acceleration is

         [tex]a = \frac{dv}{dt} = \frac{d^2x}{dt^2}[/tex]

         a = -A w² cos wt

we subtitle

         a = - 0.65 2.51² cos (2.51  0.448)

         a = - 1.76 m / s²

b) the maximum acceleration occurs when the cosine is ±1

        a = A w²

        a = 0.65  2.51²

        a = 4.10 m / s²

Let's use Newton's second law

        F = m a

        F = 5 4.1

        F = 20.5 N

c) The angular velocity is given by

          w² = k / m

let's find the spring constant

          k = m w²

          k = 5 2.51²

          k = 31.5 N / m

therefore if the block is exchanged for another with mass m'= 2.5 kg

         w = √(31.5 / 2.5)

         w = 3.55 rad / s

Answer:

V = 20m/s

Explanation:

Given the following data;

Acceleration = 4m/s²

Time = 10 secs

Initial velocity = 0m/s (since it's at rest).

To find the average velocity, we would use the first equation of motion;

[tex] V = U + at[/tex]

Where;

V is the final velocity.

U is the initial velocity.

a is the acceleration.

t is the time measured in seconds.

Substituting into the equation, we have;

V = 0 + 4*10

V = 40m/s

To find the average velocity;

Average velocity = (U + V)/2

Average velocity = (0 + 40)/2

Average velocity = 40/2

Average velocity = 20m/s

Answer: I don't know my dude

Explanation:

Answer:

She changed a closed circuit to an open circuit

Explanation:

This means that she has changed from a short circuit to an open circuit. Then the correct option is C.

The stream of positive charges which flow from the positive terminal to the negative terminal of the battery attached in a circuit.

An interrupted consistency in an electrical circuit prevents current from flowing, which is what the term "OPEN CIRCUIT" refers to.

A closed circuit is comparable to a road that uses a bridge to cross a stream.

An electrical circuit in a gadget with a current rating than a typical circuit, particularly one created by unintentional component engagement and subsequent current misdirection.

In a movie, the heroine saves the day by cutting a wire before the time runs out on a timer.

This means that she has changed from a short circuit to an open circuit.

Then the correct option is C.

Learn more about electric current.

https://brainly.com/question/2264542

#SPJ5

Answer:

the number density of the protons in the beam is 3.2 × 10¹³ m⁻³

Explanation:

Given that;

diameter D = 2.0 mm

current I = 1.0 mA

K.E of each proton is 20 MeV

the number density of the protons in the beam = ?

Now, we make use of the relation between current and drift velocity

I = MeAv ⇒ 1 / eAv

The kinetic energy of protons is given by;

K = [tex]\frac{1}{2}[/tex][tex]m_{p}[/tex]v²

v = √( 2K / [tex]m_{p}[/tex] )

lets relate the cross-sectional area A of the beam to its diameter D;

A = [tex]\frac{1}{4}[/tex]πD²

now, we substitute for v and A

n = I / [tex]\frac{1}{4}[/tex]πeD² ×√( 2K / [tex]m_{p}[/tex] )

n = 4I/π eD² × √([tex]m_{p}[/tex] / 2K )

so we plug in our values;

n = ((4×1.0 mA)/(π(1.602×10⁻¹⁹C)(2mm)²) × √(1.673×10⁻²⁷kg / 2×( 20 MeV)(1.602×10⁻¹⁹ J/ev )

n =  1.98695 × 10¹⁸ × 1.6157967  × 10⁻⁵

n = 3.2 × 10¹³ m⁻³  

Therefore, the number density of the protons in the beam is 3.2 × 10¹³ m⁻³

Answer:

0.705 m/s²

Explanation:

a) The sprinter accelerates uniformly from rest and reaches a top speed of 35 km/h at the 67-m mark.

Using newton's law of motion:

v² = u² + 2as

v = final velocity = 35 km/h = 9.72 m/s, u = initial velocity = 0 km/h,  s = distance = 67 m

9.72² = 0² + 2a(67)

134a = 94.484

a = 0.705 m/s²

b) The sprinter maintains this speed of 35 km/h for the next 88 meters. Therefore:

v = 35 km/h = 9.72 m/s, u = 35 km/h = 9.72 m/s, s = 88 m

v² = u² + 2as

9.72² = 9.72² + 2a(88)

176a = 9.72² - 9.72²

a = 0

c) During the last distance, the speed slows down from 35 km/h to 32 km/h.

u = 35 km/h = 9.72 m/s, v = 32 km/h = 8.89 m/s, s = 200 - (67 + 88) = 45 m

v² = u² + 2as

8.89² = 9.72² + 2a(45)

90a = 8.89² - 9.72²

90a = -15.4463

a = -0.1716 m/s²

The maximum acceleration is 0.705 m/s² which is from 0 to 67 m mark.

Answer: an ant eater who can’t eat

Explanation:

Answer:

- the Thevenin equivalent circuit for the battery is uploaded below

- the battery delivered 117 watts of power to the starter motor

Explanation:

Given the data in the equation

diagram of the Thevenin equivalent circuit for the battery is uploaded below.

Current I = 10 A

Voltage 1 = 12 V

voltage 2 = 11.7 v

R = (V1 - V2) / I

R = (12-11.7)/10

R = 0.3 / 10

R = 0.03Ω

Thevenin equivalent circuit

[tex]R_{L}[/tex] = V2 / I = 11.7 / 10

[tex]R_{L}[/tex] = 1.17Ω

so, power delivered to the starter motor will be;

p = (V2)² / [tex]R_{L}[/tex]

P = ( 11.7 V )² / 1.17Ω

p =  136.89 / 1.17

p =  117 watts

Therefore, the battery delivered 117 watts of power to the starter motor

Answer:

some kind of chemical of which i do not know

Explanation:

Answer:

g₂ = 39 m / s²

Explanation:

Mass is the amount of matter that a body has, so it does not change, but the weight is the force with which the planet attracts this matter, this value does change

           W = m g

let's use subscript 1 for the first planet and subscript 2 for the second planet

           W₁ = m₁ g₁

           W₂ = m₂ g₂

They give us the values ​​of the masses and the value of g₁ = 7.0 m / s, let's find the value of the acceleration of gravity on Planet 2

They tell us that the weight of the two astronauts is the same therefore

          W₁ = W₂ = W

let's match the expressions

             m₁ g₁ =m₂ g₂

             g₂ = [tex]\frac{m_1}{m_2} \ g_1[/tex]

let's calculate

              g₂ = [tex]\frac{70}{80} \ 7.0[/tex]      

              g₂ = 39.2 m / s²

              g₂ = 39 m / s²

Answer: a. m = 7.7 kg

              b. V = 435.52 in³

              c. m = 1927 kg

              d. V = 335.37 cm³

              e. m = 3 kg

Explanation: Density is the ratio of mass per volume, i.e., it's the measure of an object's compactness. Its representation is the greek letter ρ.

The formula for density is

[tex]\rho=\frac{m}{V}[/tex]

Density's unit in SI is kg/m³, but it can assume lots of other units.

Some unit transformations necessary for the resolution of the question:

1 L = 1 dm³ = 1000 cm³

1 in³ = 16.3871 cm³

1 g = 0.001 kg

a. V = 1.34 L = 1340 cm³

[tex]\rho=\frac{m}{V}[/tex]

[tex]m=\rho.V[/tex]

m = 5.75 * 1340

m = 7705 g => 7.705 kg

Mass of object 1 with volume 1.34L is 7.7 kg.

b. A cube's volume is calculated as V = side³

V = 7.58³

V = 435.52 in³

Volume of object 2 is 435.52 in³.

c. Using 1 in³ = 16.3871 cm³ to change units:

V = 435.52 * 16.3871

V = 713689.4 cm³

Then, mass will be

[tex]m=\rho.V[/tex]

m = 2.7 * 713689.4

m = 1926961.4 g => 1927 kg

Mass of object 2 is 1927 kg.

d. Volume of a sphere is calculated as [tex]V=\frac{4}{3}.\pi.r^{3}[/tex]

Diameter is twice the radius, then r = 4.31 cm.

Volume is

[tex]V=\frac{4}{3}.\pi.(4.31)^{3}[/tex]

V = 335.37 cm³

Volume of object 3 is 335.37 cm³.

e. [tex]m=\rho.V[/tex]

m = 8.96 * 335.37

m = 3004.91 g => 3 kg

Mass of object 3 is 3 kg.

Answer:

F = 228.24 N

Explanation:

       where pf = final momentum = m*vf

                  p₀ = initial momentum = m*v₀

       [tex]m*v_{f} - m*v_{o} = -2*v_{o} -m*v_{o} = -3*m*v_{o} = -3*0.3kg*12.68m/s = -11.41m/s (2)[/tex]

       [tex]F_{net} = \frac{-11.41m/s}{0.05s} = -228.24 N (3)[/tex]

Answer:

I think A

Explanation:

because I don't think a unknowned number can be a division problem

Answer:

(A)  the acceleration  experienced by the proton 2.821 x 10¹² m/s²

(B) the speed of the proton is 2.67 x 10⁵ m/s

Explanation:

Given;

electric field experienced by the proton, E = 2.95 x 10⁴ N/C

charge of proton, Q = 1.6 x 10⁻¹⁹ C

mass of proton, m = 1.673 x 10⁻²⁷ kg

distance moved by the proton, d = 1.26 cm = 0.0126 m

(a)

The force experienced by the proton is calculated as;

F = ma = EQ

where;

a is the acceleration  experienced by the proton

[tex]a = \frac{EQ}{m} \\\\a = \frac{2.95\times 10^4 \ \times \ 1.6\times 10^{-19}}{1.673 \times 10^{-27}} \\\\a = 2.821 \times 10^{12} \ m/s^2[/tex]

(b) the speed of the proton is calculated;

v² = u² + 2ad

v² = 0 + (2 x 2.821 x 10¹² x 0.0126)

v² = 7.109 x 10¹⁰

v = √7.109 x 10¹⁰

v = 2.67 x 10⁵ m/s

Answer:

C

Explanation:

Hope this helps!!!!

Answer:

See explanation below

Explanation:

This is a typical exercise of free falling. In this case a rock thrown straight down from the bridge, and we are asked to determine the final velocity of the rock and it's displacement at those given times.

First, just for this problem, as the rock is going straight down, we'll say that the downward direction is positive, therefore, the following expressions to calculate velocity and speed will be:

V = V₀ + gt   (1)

X = V₀t + gt²/2   (2)

In this case, g = 9.8 m/s²

Now, let's see the displacement and velocity for each given time:

a) For  t = 0.5 s

V = 14 + (9.8)*0.5

V = 18.9 m/s

X = (14*0.5) + (9.8)(0.5)²/2

X = 7 + 1.225

X = 8.225 m

b) For t = 1.00 s

V = 14 + (9.8)*1

V = 23.8 m/s

X = (14*1) + (9.8)(1)²/2

X = 14 + 4.9

X = 18.9 m

c) For t = 1.5 s

V = 14 + (9.8)*1.5

V = 28.7 m/s

X = (14*1.5) + (9.8)(1.5)²/2

X = 21 + 11.025

X = 32.025 m

d) For t = 2 s

V = 14 + (9.8)*2

V = 33.6 m/s

X = (14*2) + (9.8)(2)²/2

X = 28 + 19.6

X = 47.6 m

e) For t = 2.50 s

V = 14 + (9.8)*2.5

V = 38.5 m/s

X = (14*2.5) + (9.8)(2.5)²/2

X = 35 + 30.625

X = 65.625 m

Hope this helps

Answer:

4.8mph

Explanation:

Speed= Distance/time

Speed= 26.2/5.5

= 4.76mph

( To the nearest tenth ) = 4.8mph

Answer:

38.7 mph

Explanation:

I just add all the numbers together then divided them by 4, which is the amount of numbers you gave.

Answer:

C the metal handle because it is a good conductor

Answer:

D.

Explanation:

Although the metal handle will last longer, if heated up enough it could burn her hand.