I need helpppp for brainlyy

HELP NOWWWWW PLEASE

Finger [1]

Answer:it is A

Explanation:

ok

7 0

2 years ago

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A capacitor with an initial potential difference of 185 V is discharged through a resistor when a switch between them is closed

GrogVix [38]

Answer:

a. $\tau = 2.1161 s$

b. $V(18.8 \ s) = 0.0256 \ V$

Explanation:

The equation for the voltage V of discharging capacitor in an RC circuit at time t is:

$V(t) = V_0 e^{(- \frac{t}{\tau}) }$

where $V_0$ is the initial voltage, and $\tau$ is the time constant.

For our problem, we know

$V_0 = 185 \ V$

and

$V(10 \ s) = V_0 e^{(- \frac{10 \ s}{\tau}) } = 1.64 \ V$

So

$185 \ V \ e^{(- \frac{10 \ s}{\tau}) } = 1.64 \ V$

$e^{(- \frac{10 \ s}{\tau}) } = \frac{1.64 \ V}{ 185 \ V }$

$ln (e^{(- \frac{10 \ s}{\tau}) } ) = ln (\frac{1.64 \ V}{ 185 \ V })$

$- \frac{10 \ s}{\tau} = ln (\frac{1.64 \ V}{ 185 \ V })$

$\tau = \frac{-10 \s}{ln (\frac{1.64 \ V}{ 185 \ V }) }$

This gives us

$\tau = 2.1161 s$

and this is the time constant.

At t = 18.8 s we got:

$V(18.8 \ s) = 185 \ V \ e^{(- \frac{18.8 \ s}{2.1161 s}) }$

$V(18.8 \ s) = 0.0256 \ V$

4 0

3 years ago

100 + 50 + BRAINLIST PLEASE HELP!!!

irina1246 [14]

Answer:

Explanation:

1. What are the forces acting on the block when it is hanging freely from the spring scale? What is the net force on the block? What are the magnitudes of each of the forces acting on the block? Explain.

When a block is hanging freely, two forces are acting on it = tension force from the spring scale and gravity force on the block itself. The net force is zero as the block is not accelerating. The magnitudes of tension and gravity force are the same but in opposite directions.

2. What are the forces that act on the block when it is placed on the ramp and is held in place by the spring scale? What is the net force acting on the block? Explain. (Assume that the ramps are frictionless surfaces.)

There are three forces acting on the block when it is placed on the ramp and is held in place by the spring scale: as in 1, there are tension and gravity but there is a third force - reaction force from the ramp surface on the block that is perpendicular to the surface. Again the block is not moving so the net force is zero.

3. What is the magnitude of normal force acting on the block when it is resting on the flat surface? How does the normal force change as the angle of the ramp increases? Explain. (Assume that the ramps are frictionless surfaces.)

On flat surface, the normal force is equal to the gravity force of the block i.e. its weight. On a vertical surface, the normal force is equal to zero. For the angle of ramp, θ, the normal force = weight * cos θ.

6 0

3 years ago

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What is density in physics

almond37 [142]

Density is mass per volume

3 0

3 years ago

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Suppose that 1000 pollen grains slam into the abdomen of a 5.0 g bee that is hovering just above the flower. the grain's mass is

BaLLatris [955]

<span>m1 = 5g = 0.005kg v1 = 0 m2 = 1.0 x 10^-7g = 1.0x10^-10kg v2 = 7.5 v3 = ? looks like you did the formula correctly m1v1 + m2v2 = (m1+m2)v3 0 + m2v2 = (m1+m2)v3 m2v2 / (m1+m2) = v3 (1.0x10^-10)(7.5) / (0.005 + 1.0x10^-10) = v3 1.5x10^-7 = v3 However, it said the bee gets hit by 1000 pollen grains, so I would guess you have to multiply 1.0 x 10^-10 by 1000 first, unless the total mass of the 1000 grains really is 1.0 x 10^-10.</span>

7 0

3 years ago

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