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3 years ago

I need help on #18. Thanks! :)

Physics

1 answer:

serg [7]3 years ago

4 0

There are two kinds of electrical charge.
We call them 'positive' and 'negative' ... I guess nobody ever thought of better names.

One basic law of electric charges is:

Two of the same kind of charge repel each other.
One of each kind of charge attract each other.

Electrons all carry a negative charge.
So two electrons carry the SAME kind of charge, and so repel each other.

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Three solid, uniform, cylindrical flywheels, each of mass 65.0 kg and radius 1.47 m, rotate independently around a common axis t

Mkey [24]

Answer:

the angular momentum is 1015.52 kg m²/s

Explanation:

given data

mass of each flywheel, m = 65 kg

radius of flywheel, r = 1.47 m

ω1 = 8.94 rad/s

ω2 = - 3.42 rad/s

to find out

magnitude of the net angular momentum

solution

we get here Moment of inertia that is express as

I = 0.5 m r² .................1

put here value and we get

I = 0.5 × 65 × 1.47 × 1.47

I = 70.23 kg m²

and

now we get here Angular momentum that is express as

L = I × ω ...........................2

and Net angular momentum will be

L = 2 × I x ω1 - I × ω2

put here value and we get

L = 2 × 70.23 × 8.94 - 70.23 × 3.42

L = 1015.52 kg m²/s

the angular momentum is 1015.52 kg m²/s

3 0

4 years ago

What is the emf of this cell under standard conditions? Express your answer using three significant figures.

madreJ [45]

Complete Question

A voltaic cell utilizes the following reaction and operates at 298 K:

3Ce4+(aq)+Cr(s)→3Ce3+(aq)+Cr3+(aq).

What is the emf of this cell under standard conditions? Express your answer using three significant figures.

Answer:

The value is $E^o_{cell} = 2.35 V$

Explanation:

From the question we are told that

The ionic equation is

$3 Ce^{4 +} _{(aq)} + Cr _{(s)} \to 3 Ce^{3+} _{(aq)} + Cr^{3r} _{(aq)}$

Now under standard conditions the reduction half reaction is

$Ce^{4+} + e \to Ce^{3+} ; \ \ E^o_r = 1.61 V$

And the oxidation half reaction is

$Cr^{3+} + 3e^{-} \to Cr ; \ \ \ E^o_o = - 0.74 V$

The emf of this cell under standard conditions is mathematically represented as

$E^o_{cell} = E^o _r - E^o _o$

substituting values

$E^o_{cell} = 1.61 - (- 0.74)$

$E^o_{cell} = 2.35 V$

3 0

3 years ago

the gravitational force exerted on a baseball is 2.21 N down, a pitcher throws the ball horizontally with velocity 18.0 m/s by u

Ilia_Sergeevich [38]

To have a weight of 2.21N., the ball's mass is (2.21/9.8) = .226kg.
a) d = 1/2 (vt), = 1/2 (18 x .17), = 1.53m. 
b) Acceleration of the ball = (v/t), = 18/.17, = 105.88m/sec^2. 
f = (ma), = .226 x 105.88, = 23.92N.

8 0

4 years ago

Read 2 more answers

How did each scientist contributed to cell theory?

LekaFEV [45]

Answer:

Matthias Schleidan

Explanation:

because Matthias Schleiden found that all plants are composed of cells, and communicated the finding to Schwann, who had found similar structures in the cells. Other researchers confirmed the similarity, as explained in his book, where he concluded, "All living things are composed of cells and cell products.

This became the cell theory.

I learn that in my old school.

6 0

3 years ago

A radio transfers 270 j of energy electrically, 94.5 j is transferred by sound. Work out the efficiency of this radio. Give your

MakcuM [25]

Answer:

35%

Explanation:

Given data

Amount of energy transferred (Input) = 270J

Amount of energy converted to sound (Output)= 94.5J

Efficiency = output/input*100

Efficiency= 94.5/270*100

Efficiency=0.35*100

Efficiency=35%

Hence the efficiency is 35%

6 0

3 years ago