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2 years ago

A laser is used to make a CD or DVD by _____.

Physics

1 answer:

boyakko [2]2 years ago

7 0

Answer:

Explanation:

Inside your CD player, there is a miniature laser beam called a semiconductor diode laser and a small photoelectric cell an electronic light detector. The laser flashes up onto the shiny side of the CD, bouncing off the pattern of pits and lands on the disc.

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How Does Earth's gravitational force field act on objects that aren't touching Earth's surface?

natali 33 [55]

Answer:

Explanation:

Gravity is a field force since the earth does not have to actually “touch” an object to pull it toward the earth. A magnetic force is a field force that attracts or repels another magnet. Likewise, electric charges cause attracting or repelling forces without actual contact between the charges

8 0

2 years ago

A projectile has an initial horizontal velocity of 15 meters per second and an initial vertical velocity of 25 meters per second

Artyom0805 [142]

Answer:

75 m

Explanation:

The horizontal motion of the projectile is a uniform motion with constant speed, since there are no forces acting along the horizontal direction (if we neglect air resistance), so the horizontal acceleration is zero.

The horizontal component of the velocity of the projectile is

$v_x = 15 m/s$

and it is constant during the motion;

the total time of flight is

t = 5 s

Therefore, we can apply the formula of the uniform motion to find the horizontal displacement of the projectile:

$d= v_x t =(15 m/s)(5 s)=75 m$

5 0

3 years ago

A 4.5-kg, three legged stool supports a 89-kg person. If each leg of the stool has a cross-sectional diameter of 2.8 cm and the

kkurt [141]

Answer:

4.96 × 10⁵ Pa

Explanation:

F = mg

$F = (m_{person}+m_{stool})g\\\\F = (4.5 + 89)*9.8\\\\F = 916.3 N$

This force is evenly distributed on the three leg

radius, r = d/2

= 2.8 / 2

= 1.4 cm = 0.014 m

total cross sectional area of the three legs, A = 3*pi*r^2

$= 3\times\pi \times0.014^2\\\\= 1.847\times10^-^3m^2$

Pressure due to weight,

P = Weight/A

$P = / 1.847 × 10⁻³\\P = \frac{ 916.3N}{1.847\times10^-^3} \\\\P= 496032.9Pa$

P = 4.96 × 10⁵ Pa

8 0

3 years ago

13.<br>14. Why does a person feel weightlessness during freefall?

Sveta_85 [38]

Answer:

When in free fall, the only force acting upon your body is the force of gravity - a non-contact force. Since the force of gravity cannot be felt without any other opposing forces, you would have no sensation of it. You would feel weightless when in a state of free fall.

6 0

3 years ago

A single-turn circular loop of radius 6 cm is to produce a field at its center that will just cancel the earth's field of magnit

djverab [1.8K]

Answer:

The current is $I = 6.68 \ A$