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3 years ago

Name two examples where the cohesive force dominates over the adhesive force and vice versa

1 answer:

5 0

Attractive forces between molecules of the same type are called cohesive forces. ... Attractive forces between molecules of different types are called adhesive forces. Such forces cause liquid drops to cling to window panes, for example.

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When the magnetic flux through a single loop of wire increases by , an average current of 40 A is induced in the wire. Assuming

Zielflug [23.3K]

COMPLETE QUESTION:

When the magnetic flux through a single loop of wire increases by 30 Tm^2 , an average current of 40 A is induced in the wire. Assuming that the wire has a resistance of 2.5 ohms , (a) over what period of time did the flux increase? (b) If the current had been only 20 A, how long would the flux increase have taken?

Answer:

(a). The time period is 0.3s.

(b). The time period is 0.6s.

Explanation:

Faraday's law says that for one loop of wire the emf $\varepsilon$ is

$(1). \: \: \varepsilon = \dfrac{\Delta \Phi_B}{\Delta t }$

and since from Ohm's law

$\varepsilon = IR$ ,

then equation (1) becomes

$(2). \: \:IR= \dfrac{\Delta \Phi_B}{\Delta t }.$

(a).

We are told that the change in magnetic flux is $\Phi_B = 30Tm^2$ , the current induced is $I = 40A$ , and the resistance of the wire is $R = 2.5\Omega$ ; therefore, equation (2) gives

$(40A)(2.5\Omega)= \dfrac{30Tm^2}{\Delta t },$

which we solve for $\Delta t$ to get:

$\Delta t = \dfrac{30Tm^2}{(40A)(2.5\Omega)},$

$\boxed{\Delta t = 0.3s}$ ,

which is the period of time over which the magnetic flux increased.

(b).

Now, if the current had been $I =20A$ , then equation (2) would give

$(20A)(2.5\Omega)= \dfrac{30Tm^2}{\Delta t },$

$\Delta t = \dfrac{30Tm^2}{(20A)(2.5\Omega)},$

$\boxed{\Delta t = 0.6 s\\}$

which is a longer time interval than what we got in part a, which is understandable because in part a the rate of change of flux $\dfrac{\Delta \Phi_B}{\Delta t}$ is greater than in part b, and therefore , the current in (a) is greater than in (b).

7 0

3 years ago

Why cant people with aids foght out the infection?

sveta [45]

They can fight the infection but not the disease

3 0

3 years ago

Read 2 more answers

riders on the tower of doom, an amusement park ride, experience 2.0 s of free fall, after which they are slowed to a stop in 0.5

Rainbow [258]

By Newton's second law, the apparent weight of rider coming at rest is 3548 N.

According to formula, v = u + at

a = 39.2 m/ $s^{2}$

Force, F = ma

F = m(a+g)

F = apparent weight

m = mass, given = 65 kg

a = acceleration, given = 39.2 m/ $s^{2}$

g = 9.8 m/ $s^{2}$

Put these values in formula, F = m(a+g)

F = 65(39.2+9.8)

F = 3548 N

Therefore, the apparent weight of rider coming at rest is 3548 N.

Learn more about apparent weight here:- brainly.com/question/24897276

#SPJ4

6 0

1 year ago

A 12 V automobile battery is connected to an electric starter motor. The current

krek1111 [17]

Answer: $3000\ W,\ 78,000\ J$

Explanation:

Given

The voltage of the battery is $V=12\ V$

Current through the battery is $I=250\ A$

(a) Power is the product of voltage and current

Power dissipates is given by

$P=VI\\P=12\times 250\\P=3000\ W$

(b) Energy delivered

$E=P\times t$

$E=3000\times 26\\E=78,000\ J$

3 0

3 years ago

"List, from beginning to end, the stages in the weather as a cold front goes by: (a) warm air is forced upward where it cools; (

RSB [31]

Answer:

(a) warm air is forced upward where it cools;

(c) cumulonimbus or nimbo-stratus clouds form

(d) thunderstorms with heavy showers and gusty winds occur"

(b) air cools and sinks, pressure rises, rain stops;

Explanation:

A cold for front is a denser air , as that forms under the warmer and lighter air mass and this causes a low pressure along the cold form and thus causes the formation of a thunderstorm where enough moisture is present and drop in temperature occurs and in the northern hemisphere the cold front shifts the winds to from the southwest to northwest clockwise.

8 0

3 years ago

Name two examples where the cohesive force dominates over the adhesive force and vice versa​

Name two examples where the cohesive force dominates over the adhesive force and vice versa