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Marizza181 [45]

3 years ago

6

zybooks One AA battery in a flashlight stores 9400 J. The three LED flashlight bulbs consume 0.5 W. How many hours will the flas

hlight last?

1 answer:

Rom4ik [11]3 years ago

7 0

Answer:

The time for which the flashlight last is 5.23 hours.

Explanation:

Given that,

One AA battery in a flashlight stores 9400 J, E = 9400 J

Power consumed by the LED flashlight bulbs, P = 0.5 W

We need to find the time for which the flashlight last. The power of a device is given by the energy stored per unit time as :

$P=\dfrac{E}{t}$

$t=\dfrac{E}{P}$

$t=\dfrac{9400\ J}{0.5\ W}$

t = 18800 seconds

or

Since, 1 hour = 3600 seconds

t = 5.23 hours

So, the time for which the flashlight last is 5.23 hours. Hence, this is the required solution.

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What is Virtual Lab and what does people use it for and why they use it?

Dafna1 [17]

The Virtual Laboratory is an interactive environment for creating and conducting simulated experiments: a playground for experimentation. It consists of domain-dependent simulation programs, experimental units called objects that encompass data files, tools that operate on these objects

7 0

2 years ago

A brick falls to the ground. if the time for the collision of the brick and the ground is increased by a factor of 4, the force

melomori [17]

Answer:

By a factor of 1/4.

Explanation:

The impulse force that applies to an object undergoing rapid deceleration just before coming to a stop on the ground is given by the following formula,

$\\\begin{aligned}\\\small F &=\small \frac{\Delta (mV)}{\Delta T}\end{aligned}$

in which $\small \Delta (mV)$ , $\small \Delta t$ represent the change in momentum and the time taken for that change.

If one increases the time that is taken for the momentum change (which remains constant for this situation) by a factor 4 and if that new force is represented by $\small F_1$ , the following manipulation confirms the answer to this question.

$\begin{aligned}\\\small F_1 &=\small \frac{\Delta (mV)}{4\Delta t}\\\\&=\small \frac{1}{4}\times\bigg[\frac{\Delta (mV)}{\Delta t}\bigg]\\\\&=\small \frac{1}{4}F\end{aligned}$

Here $\small F$ is the force that was applied to the object previously.

#SPJ4

4 0

1 year ago

A solenoidal coil with 25 turns of wire is wound tightly around another coil with 300 turns. The inner solenoid is 25.0 cm long

joja [24]

Answer:

$5.65487\times 10^{-8}\ Wb$

$1.17\times 10^{-5}\ H$

-0.020475 V

Explanation:

$\mu_0$ = Vacuum permeability = $4\pi \times 10^{-7}\ H/m$

$N_1$ = Number of turns of coil = 25

$N_2$ = Number of turns of coil 2 = 300

$\frac{di_2}{dt}$ = Rate of current increased = $1.75\times 10^3\ A/s$

d = Diameter = 2 cm

r = Radius = $\frac{d}{2}=\frac{2}{2}=1\ cm$

A = Area = $\pi r^2$

Magnetic field in the solenoid is given by

$B=\mu_0\frac{N_2}{l}I\\\Rightarrow B=4\pi\times 10^{-7}\frac{300}{0.25}\times 0.12\\\Rightarrow B=0.00018\ T$

Magnetic flux is given by

$\phi=BA\\\Rightarrow \phi=0.00018\times \pi\times 0.01^2\\\Rightarrow \phi=5.65487\times 10^{-8}\ Wb$

The average magnetic flux through each turn of the inner solenoid is $5.65487\times 10^{-8}\ Wb$

Mutual inductance is given by

$L=\frac{N_1\phi}{i_1}\\\Rightarrow L=\frac{25\times 5.65487\times 10^{-8}}{0.12}\\\Rightarrow L=1.17\times 10^{-5}\ H$

The mutual inductance of the two solenoids is $1.17\times 10^{-5}\ H$

Induced emf is given by

$V=-L\frac{di_2}{dt}\\\Rightarrow V=-1.17\times 10^{-5}\times 1.75\times 10^3\\\Rightarrow V=-0.020475\ V$

The emf induced in the outer solenoid by the changing current in the inner solenoid is -0.020475 V

5 0

3 years ago

Superman is riding his bicycle. At the base of a hill, he has a specific amount of kinetic energy. Then he coasts up the hill wi

algol13

Answer:

D. Friction and air resistance created heat on his trip up the hill.

Explanation:

Energy transformation from one form to another is not 100% efficient. This is the postulate of the first law of thermodynamics.

Most of the energy transformation is not purely 100%.

When energy is transformed, some are usually wasted.

In this case, in moving from bottom up, Superman produced some heat and encountered air resistance.
To reach the top, he must have overcome the resistance and produce enough heat to power him through.
This reduces the amount of potential energy that should have been the same as the kinetic energy down below.

7 0

3 years ago

2. Compare the names of the metal elements by themselves to their names what they are part of andows

steposvetlana [31]

this question is unclear. please specify.

4 0

3 years ago