Please help me ejnfmwkefwefm i dont wanna fail

If you are given values for, Ay, and At, which kinematic equation could be used to find ūo ?

vesna_86 [32]

You're not given the acceleration $\vec a$ , so you should use the equation that doesn't involve it (the last choice).

4 0

3 years ago

after a circuit has been turned off, so it is important to make sure they are discharged before you touch them. Suppose a 120 mF

Snezhnost [94]

Answer:

The time is $110.16\times10^{-3}\ sec$

Explanation:

Given that,

Capacitor = 120 μF

Voltage = 150 V

Resistance = 1.8 kΩ

Current = 50 mA

We need to calculate the discharge current

Using formula of discharge current

$i_{0}=\dfrac{V_{0}}{R}$

Put the value into the formula

$i_{0}=\dfrac{150}{1.8\times10^{3}}$

$i_{0}=83.3\times10^{-3}\ A$

We need to calculate the time

Using formula of current

$i=\dfrac{V_{0}}{R}e^{\frac{-t}{RC}}$

Put the value into the formula

$50=\dfrac{150}{1.8\times10^{3}}e^{\frac{-t}{RC}}$

$\dfrac{50}{83.3}=e^{\frac{-t}{RC}}$

$\dfrac{-t}{RC}=ln(0.600)$

$t=0.51\times1.8\times10^{3}\times120\times10^{-6}$

$t=110.16\times10^{-3}\ sec$

Hence, The time is $110.16\times10^{-3}\ sec$

4 0

3 years ago

The angle of incidence of a light ray on a concave mirror is the same as the angle of reflection of that light ray. Question 23

asambeis [7]

I think it depend on the curvature of the reflective surface, right? if it is an Mirror, then the angles should mirror itself.

3 0

3 years ago

When a 4-μf capacitor has a potential drop of 20 v across its plates, how much electric potential energy is stored in this capac

Genrish500 [490]

Thew energy stored in a capacitor of capacitance $C$ and voltage between the plates $V$ is

$E=\frac{1}{2} CV^2$ .

Substituting numerical value

$E=\frac{1}{2}(4*10^{-6}) (20)^2\\ E=800\; \mu J$

7 0

4 years ago

Which of the following statements is true?

Maurinko [17]

Answer:

Concrete absorbs visible light and re-radiates it as infrared energy.

Explanation:

As we know that concrete will not reflect 100% light incident on it but it will absorb few energy and remaining energy is reflected back.

So here when visible light incident on the concrete then few of its energy is absorbed by is and then the remaining energy is reflected back.

Since the reflected energy must be less than the energy which incident on the concrete so here we will say that the reflected waves must be of less frequency range

so here most appropriate energy range of reflected wave is infrared waves

so here correct answer will be

Concrete absorbs visible light and re-radiates it as infrared energy.

6 0

3 years ago

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