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pickupchik [31]
2 years ago
9

An optical disk drive in your computer can spin a disk up to 10,000 rpm (about 1045 rad / s). if a particular disk is spun at 79

2.7 rad / s while it is being read, and then is allowed to come to rest over 0.234 seconds, what is the magnitude of the average angular acceleration of the disk?
Physics
1 answer:
NeX [460]2 years ago
4 0
(i) |α| = 235.6rad.s / 0.502s = 469 rad/s²
(ii) tang a = α*r = 469rad/s² * 0.12m / 2*11 = 2.56 m/s²
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A majorette in the Rose Bowl Parade tosses a baton into the air with an initial angular velocity of 2.5 rev/s. If the baton unde
oksian1 [2.3K]

Answer:

14 rev

Explanation:

w_{o} = initial angular velocity = 2.5 revs⁻¹

w = final angular velocity = 0.8 revs⁻¹

\alpha = Angular acceleration = - 0.2 revs⁻²

\theta = Angular displacement

Using the equation

w^{2} = w_{o}^{2} + 2 \alpha \theta\\0.8^{2} = 2.5^{2} + 2 (- 0.2) \theta\\ \theta = 14 rev

So the number of revolutions are 14

4 0
2 years ago
A circular coil 17.0 cm in diameter and containing nine loops lies flat on the ground. The Earth's magnetic field at this locati
sergeinik [125]

Answer:

The torque in the coil is  4.9 × 10⁻⁵ N.m  

Explanation:

T = NIABsinθ

Where;

T is the  torque on the coil

N is the number of loops = 9

I is the current = 7.8 A

A is the area of the circular coil = ?

B is the Earth's magnetic field = 5.5 × 10⁻⁵ T

θ is the angle of inclination = 90 - 56 = 34°

Area of the circular coil is calculated as follows;

A = \frac{\pi d^2}{4} \\\\A = \frac{\pi 0.17^2}{4} =0.0227 m^2

T = 9 × 7.8 × 0.0227 × 5.5×10⁻⁵ × sin34°

T = 4.9 × 10⁻⁵ N.m

Therefore, the torque in the coil is  4.9 × 10⁻⁵ N.m

5 0
2 years ago
A skateboarder travels on a horizontal surface with an initial velocity of 3.2 m/s toward the south and a constant acceleration
Naddika [18.5K]

Answer:

A. 0.432

B. -1.92

C. 1.44 units/second

D. -3.2 units/second

Explanation:

A. To calculate her x position, we just use the following equation of motion to find the distance traveled:

    s=u*t+\frac{1}{2} (a*t^2)

here s = displacement

t = time (in seconds)

a = acceleration

Solving for the distance, we get:

s = 0 * 0.6 + \frac{1}{2}(2.4 * 0.6^2)

s = 0.432 m

Since 0.432 meters east is equals to 0.432 meter in the positive x-direction, the x position is also 0.432.

B. Since the skater has a constant v - velocity of -3.2 m/s, (south means negative y axis), the total distance traveled is:

Distance = speed * time = -3.2 * 0.6 = -1.92 m

The answer is -1.92 units in the y-axis.

C. The x velocity component is the final speed in the east direction, which is going to be:

v^2 - u^2=2*a*s

v^2 = 2*2.4*0.432

v = 1.44 units/second (in positive x direction)

D. Her y velocity component does not change, since the velocity towards the south is a constant 3.2 m/s

Thus the answer is -3.2 units/second in the y-axis.

8 0
2 years ago
A cyclist moving towards right with an acceleration of 4m/s² at t = 0 he has travelled 5 m moving towards the right at 15 m/s wh
ira [324]

Answer:

x=2t^2+15t+5

Explanation:

x=\frac{1}{2}at^2+v_0t+x_0

4 0
2 years ago
The index of refraction for silicate flint glass is 1.66 for violet light that has a wavelength in air equal to 400 nm and 1.61
nikitadnepr [17]

Answer:

(a) Angle of incidence for violet is more than the angle of incidence for red

(b) 2.4°

Explanation:

refractive index for violet , v = 1.66

refractive index for red, nR = 1.61

wavelength for violet, λv = 400 nm

wavelength for red, λR = 700 nm

Angle of refraction, r = 30°

(a) Let iv be the angle of incidence for violet.

Use Snell,s law

nv = Sin iv / Sin r

1.66 = Sin iv / Sin 30

Sin iv = 0.83

iv = 56°

Use Snell's law for red

nR  = Sin iR / Sin r  

where, iR be the angle of incidence for red

1.61 = Sin iR / Sin 30

Sin iR = 0.805

iR = 53.6°

So, the angle of incidence for violet is more than red.

(b) iv - iR = 56° - 53.6° = 2.4°

4 0
2 years ago
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