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3 years ago

5

g A CD is spinning on a CD player. You open the CD player to change out the disk and notice that the CD comes to rest after 15 r

evolutions with a constant deceleration of 120 r a d s 2 . What was the initial angular speed of the CD

1 answer:

Umnica [9.8K]3 years ago

7 0

Answer:

$\omega_1=150rads/sec$

Explanation:

From the question we are told that:

Number of Revolution $N=15=30\pi$

Deceleration $d= -120 rads/2$

Generally the equation for initial angular speed $\omega_1$ is mathematically given by

$\omega_2^2=\omega_1^2 +2(d)(N)$

$0=\omega_1^2 +2(-120)(20 \pi)$

$\omega_1^2=7200 \pi$

$\omega_1=150rads/sec$

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An airplane is flying in a horizontal circle at a speed of 480 km/h (). If its wings are tilted at angle =40° to the horizontal

german

Answer:

$R = 2162 m$

Explanation:

When wings of the airplane makes an angle of 40 degree with the horizontal so here we can say that force due to air is having two components

$F_y = mg$

$F_x = \frac{mv^2}{R}$

now we know that

$F_y = F cos40$

$F_x = F sin40$

also we know that

$v = 480 km/h$

$v = 133.3 m/s$

now plug in all data in above equations

$tan 40 = \frac{v^2}{Rg}$

$R = \frac{v^2}{g tan40}$

$R = \frac{133.3^2}{9.8 tan40}$

$R = 2162 m$

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3 years ago

Frame S' passes frame S in the usual way. Two events are simultaneous in S'.

yuradex [85]

Answer:

c)They can also be simultaneous in S if their separation is zero.

Explanation:

By relativity theory, we can say two events when seen from two different reference frames can only be simultaneous when they are at the same space location and occur simultaneously in at least one reference frame, therefore when Frame S′ usually passes Frame S. Two occurrences in S′ are simultaneous, therefore these occurrences can be simultaneous in S when their separation is 0 (that is they are at the same location)

And therefore option c. If their separation is zero, they can also be simultaneous in S.

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3 years ago

Record the lengths of the sides of ABC and ADE.

ivann1987 [24]

Can you show the rest of the problem

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3 years ago

A theory is a way of explaining observations. true or false.

Natasha_Volkova [10]

I think its true. hope this helps.

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4 years ago

Read 2 more answers

A thin, light wire 75.2 cm long having a circular cross section 0.560 mm in diameter has a 25.2 kg weight attached to it, causin

blsea [12.9K]

Answer:

The stress is calculated as $1.003\times 10^{9}\ Pa$

Solution:

As per the question:

Length of the wire, l = 75.2 cm = 0.752 m

Diameter of the circular cross-section, d = 0.560 mm = $0.560\times 10^{- 3}\ m$

Mass of the weight attached, m = 25.2 kg

Elongation in the wire, $\Delta l = 1.10\ mm = 1.10\times 10^{- 3}\ m$

Now,

The stress in the wire is given by:

$Stress,\ \sigma = \frac{Force,\ F}{Area,\ A}$ (1)

Now,

Force is due to the weight of the attached weight:

F = mg = $25.2\times 9.8 = 246.96\ N$

Cross sectional Area, A = $\pi (\frac{d}{2})^{2} = \pi (\frac{0.560\times 10^{- 3}}{2})^{2} = 2.46\times 10^{- 7}\ m^{2}$

Using these values in eqn (1):

$\sigma = \frac{246.96}{2.46\times 10^{- 7}} = 1.003\times 10^{9}\ Pa$

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3 years ago