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3 years ago

What is current density?? Tell it's formula pls

1 answer:

8 0

Current Density is the amount of current that a conductor can safely carry without undue heating per cross - sectional area.

Current Density = Current carrying capacity/Area

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The volume of a cylindrical tin can with a top and a bottom is to be 16π cubic inches. If a minimum amount of tin is to be used

sergiy2304 [10]

Answer:

h = 4 in

Explanation:

GIVEN DATA:

volume of tin $= 16 \pi$

we know that

volume of cylinder is $v = \pi r^2 h$

so,

$16 \pi = \pi r^2 h$

$16 = r^2 h$

$r = \sqrt{\frac{16}{h}}$

construct formula for surface area

$S = 2\pi r^2 + 2\pi rh$

$S = \frac{2v}{h} + 2 \sqrt{v \pi h}$

minimize the function wrt h

$S' = \frac{2v}{h^2} + \sqrt{\frac{v \pi}{h} = 0$

solving for h we have

$h = [\frac{4 v}{\pi}]^{1/3}$

we kow $v = 16 \pi$ so

h = 4 in

8 0

3 years ago

PLS HELP WILL MARK BRAINLIEST

MariettaO [177]

Answer:

2.835 Watts

Explanation:

P = I²R

P = 1.5² × 1.26

P = 2.835 Watts

3 0

3 years ago

Read 2 more answers

I need help with these Physics problems

adoni [48]

Answer:

1. 3 m

2. 27 s

Explanation:

1. "A car traveling at +33 m/s sees a red light and has to stop. If the driver can accelerate at -5.5 m/s², how far does it travel?"

Given:

v₀ = 33 m/s

v = 0 m/s

a = -5.5 m/s²

Unknown: Δx

To determine the equation you need, look for which variable you don't have and aren't solving for. In this case, we aren't given time and aren't solving for time. So look for an equation that doesn't have t in it.

Equation: v² = v₀² + 2aΔx

Substitute and solve:

(0 m/s)² = (33 m/s)² + 2(-5.5 m/s²) Δx

Δx = 3 m

2. "A plane starting from rest at one end of a runway accelerates at 4.8 m/s² for 1800 m. How long did it take to accelerate?"

Given:

v₀ = 0 m/s

a = 4.8 m/s²

Δx = 1800 m

Unknown: t

Equation: Δx = v₀ t + ½ a t²

Substitute and solve:

1800 m = (0 m/s) t + ½ (4.8 m/s²) t²

t ≈ 27 s

4 0

3 years ago

Help meh in this question plzzz <br>

iragen [17]

The Moment of Inertia of the Disc is represented by $I = \frac{15}{32}\cdot M\cdot R^{2}$ . (Correct answer: A)

Let suppose that the Disk is a Rigid Body whose mass is uniformly distributed. The Moment of Inertia of the element is equal to the Moment of Inertia of the entire Disk minus the Moment of Inertia of the Hole, that is to say:

$I = I_{D} - I_{H}$ (1)

Where:

$I_{D}$ - Moment of inertia of the Disk.

$I_{H}$ - Moment of inertia of the Hole.

Then, this formula is expanded as follows:

$I = \frac{1}{2}\cdot M\cdot R^{2} - \frac{1}{2}\cdot m\cdot \left(\frac{1}{2}\cdot R^{2} \right)$ (1b)

Dimensionally speaking, Mass is directly proportional to the square of the Radius, then we derive the following expression for the Mass removed by the Hole ( $m$ ):