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Levart [38]
2 years ago
15

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

Physics
1 answer:
boyakko [2]2 years ago
7 0

Answer:

A)  

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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Block B (of mass m) is initially at rest. Block A (of mass 3m) travels toward B with an initial speed v0 (vee nought) and collid
NeTakaya

Answer:

The maximum height reached by the two blocks is approximately 0.1147959 × v₀²

Explanation:

The mass of block B = m

The mass of block A = 3·m

The initial velocity of block B, v₂ = 0 m/s

The initial velocity of block A, v₁ = v₀

The amount of friction between the blocks and the surface = Negligible friction

By the Law of conservation of linear momentum, we have;

Total initial momentum = Total final momentum

3·m·v₁ + m·v₂ = (3·m + m)·v₃ = 4·m·v₃

Plugging in the values for the velocities gives;

3·m × v₀ + m × 0 = (3·m + m)·v₃ = 4·m·v₃

∴ 3·m × v₀ =  4·m·v₃

\therefore v_3 = \dfrac{3}{4} \times v_0 = 0.75 \times v_0

The kinetic energy, K.E. of the combined blocks after the collision is given as follows;

K.E. = 1/2 × mass × v²

\therefore K.E. = \dfrac{1}{2} \times 4\cdot m \times \left (\dfrac{3}{4} \cdot v_0 \right )^2 = \dfrac{9}{8} \cdot m\cdot v_0^2

The potential energy, P.E., gained by the two blocks at maximum height = The kinetic energy, K.E., of the two blocks before moving vertically upwards

The potential energy, P.E. = m·g·h

Where;

m = The mass of the object at the given height

g = The acceleration due to gravity

h = The height at which the object of mass, 'm', is located

Therefore, for h = The maximum height reached by the two blocks, we have;

P.E. = K.E.

m \cdot g \cdot h =  \dfrac{9}{8} \cdot m\cdot v_0^2

h = \dfrac{\dfrac{9}{8} \cdot m\cdot v_0^2}{m \cdot g }  = \dfrac{9}{8} \cdot \dfrac{ v_0^2}{ g }  =  \dfrac{9}{8} \cdot \dfrac{ v_0^2}{ 9.8} = \dfrac{42}{392} \cdot  v_0^2 \approx 0.1147959   \cdot  v_0^2

The maximum height reached by the two blocks, h ≈ 0.1147959·v₀².

7 0
2 years ago
Which would best help a student determine the net force acting on a rollercoaster car as it moves from one point on its track to
Lelu [443]

Answer:

you can show them a vid

Explanation:

6 0
3 years ago
If the acceleration of motorboat is 4m/s^2 and the motorboat stsrtsfrol.Rest what is velocity after 6.0 s
UkoKoshka [18]

Answer:

24 m/s

Explanation:

Using v = u + at where u = initial velocity of the motorboat = 0 m/s (since the boat starts from rest), a = acceleration = 4 m/s², t = time = 6 s and v = velocity of the motorboat after 6.0 s.

Substituting the values of the variables into the equation, we have

v = u + at

= 0 m/s + 4 m/s² × 6.0 s

= 0 m/s + 24 m/s

= 24 m/s

3 0
3 years ago
Sam is about to drop a golf ball from his hand. As the falls, its _____ energy will decrease and it's ______ energy will increas
Nikitich [7]

Answer: a. potential b. kinetic

Explanation:

3 0
3 years ago
Read 2 more answers
MathPhys May you help me once again?
Maru [420]

Answer:

2. Same force; same impulse; Mini Cooper has greater change in velocity

4. Same momentum

6. It is distributed to the two halves

Explanation:

I will do the even problems as examples.

2. From Newton's third law, we know the bulldozer and Mini Cooper will experience equal but opposite forces.  So the magnitude of the force is the same.

Impulse is force times time.  Since the force is the same, and the amount of time is the same, then the impulse is the same.

Impulse is equal to change in momentum, or mass times change in velocity.  Since the Mini Cooper has the smaller mass, it has the greater change in velocity.

4. Momentum is mass times velocity.  The weight of the rover is different on Mars than on Earth, but the mass is still the same.  Therefore, if the rover moves at the same speed, it will have the same momentum.

6. The pencil's momentum is conserved.  When the pencil breaks in half, half the momentum goes to one half of the pencil, and half the momentum goes to the other half of the pencil.

6 0
3 years ago
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