Numatoms is initially 7. what is numatoms after: numatoms += 5?

Find the final price of a 10-speed bike whose original price was $150.00 with a 10% discount and a 6% sales tax.

goldenfox [79]

We have given
original price =150.00
discount=10%=0.1
sales tax=6%=.06
now
discount=150*0.1=15cost of bike after discount =150-15=135
sales tax=135*.06=8.1
final price =cost of bike after discount +sales tax
final price=135+8.1
final price=143.1

5 0

3 years ago

A sample of a material has 200 radioactive particles in it today. Your great-grandmother measured 400 radioactive particles in i

uysha [10]

It will have 100 radioactive particles.

6 0

4 years ago

Read 2 more answers

What inductance l would be needed to store energy e=3.0kwh (kilowatt-hours) in a coil carrying current i=300a?

myrzilka [38]

The formula for the energy stored in the magnetic field of an inductor is:

E = (1/2) (inductance) (current)² .

In the present situation:

Energy = (3 kilo-watt-hour) x (1,000 / kilo) x (joule/watt-sec) x (3,600 sec/hr)

   = (3 · 1000 · 3,600) (kilo·watt·hr·joule·sec / kilo·watt·sec·hr)

   =    1.08 x 10⁷ joules .

Now to find the inductance:

   E = (1/2) (inductance) (current)²

   (1.08 x 10⁷ joules) = (1/2) (inductance) (300 Amp)²

   (2.16 x10⁷ joules) = (inductance) (300 Amp)²

   Inductance = (2.16 x10⁷ joules) / (300 Amp)²

=   2.16 x10⁷ / 90,000    Henrys

   I get    240 Henrys .

This is a big inductance. Possibly the size of your house.
To get a big inductance, you want to wind the coil
with a huge number of turns of very fine wire, in
a small space.
In this case, however, if you plan on running 300A through
your coil, it'll have to be wound with a very thick conductor ...
like maybe 1/4-inch solid copper wire, or even copper tubing,
You have competing requirements.
There are cheaper, easier, better ways to store 3 kWh of energy.
In fact, a quick back-of-the-napkin calculation says that
3 or 4 car batteries will do the job nicely.

5 0

3 years ago

The current through a certain heater wire is found to be fairly independent of its temperature. If the current through the heate

bearhunter [10]

Answer:

(c) increase by a factor of four

Explanation:

the formular for the relationship between energy and current is E= I²Rt (Heat energy)

the heater is fairly independent of its temperature , and given the time to be constant.

with the current being doubled,

E = I² Rt

E/ I² = K

$\frac{E1}{I1^{2} }$ = $\frac{E2}{I2^{2} }$

E2 = $\frac{E1* I1^{2} }{I1^{2} }$

I2 = 2* I1

E2 = E1 * 4*I1² / I1²

dividing , we have that E2 = 4 * E1

which means during the same time interval the amount of energy will increase by a factor of four.

7 0

4 years ago

Two particles, each with charge Q, and a third charge q, are placed at the vertices of an equilateral triangle as shown. The tot

Gelneren [198K]

Answer:

D. The total force on the particle with charge q is perpendicular to the bottom of the triangle.

Explanation:

The image is shown below.

The force on the particle with charge q due to each charge Q = $\frac{kQq}{r^{2} }$

we designate this force as N

Since the charges form an equilateral triangle, then, the forces due to each particle with charge Q on the particle with charge q act at an angle of 60° below the horizontal x-axis.

Resolving the forces on the particle, we have

for the x-component

$N_{x}$ = N cosine 60° + (-N cosine 60°) = 0

for the y-component

$N_{y}$ = -f sine 60° + (-f sine 60) = -2N sine 60° = -2N(0.866) = -1.732N

The above indicates that there is no resultant force in the x-axis, since it is equal to zero ( $N_{x}$ = 0).

The total force is seen to act only in the y-axis, since it only has a y-component equivalent to 1.732 times the force due to each of the Q particles on q.

The total force on the particle with charge q is therefore perpendicular to the bottom of the triangle.

5 0

4 years ago