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3 years ago

Which device typically use DC current to operate?

Physics

2 answers:

aleksklad [387]3 years ago

5 0

Answer: C. wrist-watch

Explanation:

Alternating current refers to the current which changes direction. The current which is supplied to our home is alternating current which is used to run home appliances such as television, washing machine, electric hair dryer, ceiling fan etc.

A current which flows in only one direction is known as direct current. A cell or a battery is a source of direct current. A wrist watch runs on direct current provided by a cell attached to it.

Artemon [7]3 years ago

4 0

C.) Wristwatch uses DC current to operate..

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Can someone please help, ty!

lyudmila [28]

Answer:hypothesis: the plant died of lack of light,moisture,or water

Explanation:

to test my hypothesis i put a plant in a room at room temp and repeat how i grew it,and observe what went wrong. hope this helps=)

5 0

4 years ago

If a rock is dropped from the top of a tower at the front of it and takes 3.6 seconds to hit the ground. Calculate the final vel

expeople1 [14]

Answer:

35.28m/s; 63.50m

Explanation:

<u>Given the following data;</u>

Time, t = 3.6 secs

Since it's a free fall, acceleration due to gravity = 9.8m/s²

Initial velocity, u = 0

To find the final velocity, we would use the first equation of motion;

$V = u + at$

Substituting into the equation, we have;

$V = 0 + 9.8 * 3.6$

V = 35.28m/s

Therefore, the final velocity of the penny is 35.28m/s.

To find the height, we would use the second equation of motion;

$S = ut + \frac {1}{2}at^{2}$

Substituting the values into the equation;

$S = 0(3.6) + \frac {1}{2}*9.8*(3.6)^{2}$

$S = 0 + 4.9*12.86$

$S = 0.5 *36$

S = 63.50m

Therefore, the height of the tower is 63.50m.

6 0

3 years ago

A spring with spring constant 11.5 N/m hangs from the ceiling. A 490 g ball is attached to the spring and allowed to come to res

Natalija [7]

Answer:

The time constant is $\tau = 17.5 \ s$

Explanation:

From the question we are told that

The spring constant is $k = 11.5 \ N/m$

The mass of the ball is $m_b = 490 \ g = 0.49 \ kg$

The amplitude of the oscillation t the beginning is $x = 6.70 cm = 0.067 \ m$

The amplitude after time t is $x_t = 2.20 cm = 0.022 \ m$

The number of oscillation is $N = 30$

Generally the time taken to attain the second amplitude is mathematically represented as

$t = N * T$ Here T is the period of oscillation

$t = N * 2\pi \sqrt{\frac{m}{k} }$

=> $t = 30 * 2 * 3.142 * \sqrt{\frac{ 0.490}{11.5} }$

=> $t = 38.88 \ s$

Generally the amplitude at time t is mathematically represented as

$x(t) = x e^{-\frac{at}{2m} }$

Here a is the damping constant so

at $t = 38.88 \ s$ , $x_t = 2.20 cm = 0.022 \ m$

$0.022 = 0.067 e^{-\frac{a * 38.88}{2 * 0.490} }$

=> $0.3284 = e^{-\frac{a * 38.88}{2 * 0.490} }$

taking natural log of both sides

=> $ln(0.3284 ) = -\frac{a * 38.88}{2 * 0.490} }$

=> $a = 0.028$

Generally the time constant is mathematically represented as

$\tau = \frac{m}{a}$

=> $\tau = \frac{0.490}{ 0.028}$

=> $\tau = 17.5 \ s$

4 0

3 years ago

7. An astronaut weighs 900N on earth. On the moon, he weighs 150N. Calculate the

noname [10]

Answer:

Moons’ gravitational strength = weight of astronaut on the moon / mass of astronaut.

= 150 / 90 = 1.67 Nkg-1

Explanation:

7 0

3 years ago

How do scientist determine the the number of iso types?

mash [69]

If you are talking about Isotopes then I believe it is the amount of atoms that have different amounts of neutrons ,but the same number of protons.

3 0

3 years ago