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1 year ago

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A certain alarm clock ticks four times each second, with each tick representing half a period. The balance wheel consists of a t

hin rim with radius 0.54 cm , connected to the balance staff by thin spokes of negligible mass. The total mass of the balance wheel is 0.95 g .Part AWhat is the moment of inertia of the balance wheel about its shaft?Express your answer using two significant figures.Part BWhat is the torsion constant of the hairspring?Express your answer using two significant figures.

1 answer:

Semenov [28]1 year ago

3 0

Answer:

a. $I=2.77x10^{-8} kg*m^2$

b. $K=4.37 x10^{-6} N*m$

Explanation:

The inertia can be find using

a.

$I = m*r^2$

$m = 0.95 g * \frac{1 kg}{1000g}=9.5x10^{-4} kg$

$r=0.54 cm * \frac{1m}{100cm} =5.4x10^{-3}m$

$I = 9.5x10^{-4}kg*(5.4x10^{-3}m)^2$

$I=2.77x10^{-8} kg*m^2$

now to find the torsion constant can use knowing the period of the balance

b.

T=0.5 s

$T=2\pi *\sqrt{\frac{I}{K}}$

Solve to K'

$K = \frac{4\pi^2* I}{T^2}=\frac{4\pi^2*2.7702 kg*m^2}{(0.5s)^2}$

$K=4.37 x10^{-6} N*m$

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Two astronauts on opposite ends of a spaceship are comparing lunches. One has an apple, the other has an orange. They decide to

german

Answer: v= 1.23 m/s θ = 75.3º

Explanation:

First of all, we define the direction in which both fruits are tossed as the x axis, so all initial momenta have horizontal components only.

Now, if no external forces act during collision (due to the infinitesimal time during which collision takes place) momentum must be conserved.

As momentum is a vector, both components must be conserved, so we can write the following equations:

p₁ₓ = p₂ₓ ⇒ -m₁ . vi₁ +m₂. vi₂ = m₁ . vf₁ . cos θ (1)

p₁y = p₂y ⇒ 0 =m₂ . vf₂ - m₁. vf₁. sin θ (2)

Replacing by the values of m1, m₂, vi₁, vi₂, and vf₂, we can calculate the value of the angle θ, that the apple forms with the horizontal, as follows:

(1) -0.13 Kg. 1.05 m/s + 0.15 Kg. 1.18 m/s = 0.13. vf . cos θ

(2) 0.15 Kg. 1.03 m/s = 0.13 vf. sin θ

sin θ / cos θ = 3.82 ⇒ tg θ = 3.82 ⇒ θ = arc tg (3.82) = 75.3º

Replacing this value of θ in (2), we get:

0.15 kg. 1.03 m/s = 0.13 vf . sin 75.3º = 0.13 . vf . 0.967

Solving for vf, we get:

vf = 0.15 kg. 1.03 m/s / 0.13. 0.967 = 1.23 m/s

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1 year ago

Have you ever chewed on a wintergreen mint in front of a mirror in the dark? If you have, you may have noticed some sparks of li

lutik1710 [3]

Answer:

Part a)

$E = 3.66 eV$

Part b)

$\lambda = 508.5 nm$

Explanation:

Part a)

change in the energy due to decay of photon is given as

$E = h\nu$

here we know that

$\nu = 8.88 \times 10^{14} Hz$

now we have

$E = (6.6 \times 10^{-34})(8.88 \times 10^{14})$

$E = 5.86 \times 10^{-19} J$

$E = 3.66 eV$

Part b)

While electron return to its ground state it will emit a photon of energy 2/3rd of the total energy

so we have

$\Delta E = \frac{2}{3}(3.66 eV)$

$\Delta E = 2.44 eV$

now to find the wavelength we have

$\Delta E = \frac{hc}{\lambda}$

$2.44 = \frac{1242}{\lambda}$

$\lambda = 508.5 nm$

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2 years ago

A recipe for candy requires that the liquid ingredients be stirred constantly until the liquid reaches a temperature of 140°C. W

lara31 [8.8K]

Sample Response: A wooden spoon will prevent the person’s hand from burning because wood is an insulator. An insulator slows the transfer of thermal energy so that very little thermal energy from the hot liquid will transfer to the person’s hand.

include:

-A wooden spoon will prevent the person’s hand from burning.

-Wood is an insulator.-An insulator slows the transfer of thermal energy.<span>-The wooden spoon will transfer very little thermal energy to the person’s hand.

you're welcome lol</span>

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2 years ago

Read 2 more answers

Older televisions display a picture using a device called a cathode ray tube, where electrons are emitted at high speed and coll

Vaselesa [24]

Answer:

a) $3*10^{-9}\ s$

b) 2.36 cm

Explanation:

a) The horizontal distance = x = 6 cm

1 cm = 0.01 m

6 cm = 6 cm * 0.01 m/cm = 0.6 m

Therefore the time taken (t) by the electron to travel from the emission point to the screen can be gotten from:

x = t * $V_i$

$V_i=initial\ velocity=2*10^7\ m/s$

$x=tV_i\\\\t=\frac{x}{V_i}\\ \\t=\frac{0.06}{2*10^7}\\ \\t=3*10^{-9}\ m/s$

b) The vertical distance (y) traveled by the electon before it hits the screen is given by:

$y=\frac{1}{2}at^2\\ \\a=upward\ acceleration=5.25*10^{15}\ m/s^2\\\\Substituting:\\\\y=\frac{1}{2}*5.25*10^{15}* (3*10^{-9})\\\\y=0.0236\ m\\y=2.36\ cm$

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1 year ago

What is the magnitude of the external force f necessary to hold the cart motionless at point c?

kodGreya [7K]

The same amount of force that the cart is using nothing more nothing less

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