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4 years ago

A construction worker uses an electrical device to attract fallen nails and sharp objects

Physics

1 answer:

Vinil7 [7]4 years ago

8 0

Answer:

is the last one, a magnetic wave and electrical current moving in opposite directions

Explanation:

opposite directions always attract in magnetic waves and fields

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An object is placed 9.5 cm in front of a convex spherical mirror. Its image forms 3.2 cm behind the mirror. What is the radius o

o-na [289]

Using the mirror formula.

1/v + 1/u = 1/f

1/9.5 + 1/3.2 = 1/f

1/f = 3.2 + 9.5 / 9.5 * 3.2

1/f = 4.82 cm

Radius = 2f

Radius = 2 x 4.82

Radius = 9.64 cm

8 0

4 years ago

Read 2 more answers

Four model rockets are launched in a field. The mass of each rocket and the

TiliK225 [7]

Answer: it is rocket 2

Explanation: I just took the test

Hope it's the right answer for you

4 0

4 years ago

A circuit consists of four 100W lamps

Ksivusya [100]

Complete question is;

A circuit consists of four 100-W lamps connected in parallel across a 230-V supply. Inadvertently, a voltmeter has been connected in series with the lamps. The resistance of the voltmeter is 1500 Ω and that of the lamps under the conditions stated is six times their value then burning normally. What will be the reading of the voltmeter?

Answer:

150.42 V

Explanation:

We are told that the circuit consists of four 100W lamps.

We know that Power is given by the equation;

P = V²/R

Thus;

R = V²/P

Now, we are told that the four lamps are connected in parallel across a 230V supply.

Thus, V = 230 V

So resistance, R = 230²/100

R = 529 Ω

We are told that the resistance of the lamps under the conditions stated is six times their value when burning normally.

Thus, total resistance of each lamp under the conditions = 529 × 6 = 3174 Ω

So, since they are connected in parallel, equivalent resistance for each lamp = 3174/4 = 793.5 Ω

Now, since this resistance is connected in series with the voltmeter resistance of 1500 Ω

Therefore, total circuit resistance = 1500 + 793.5 = 2293.5 Ω

Thus;

circuit current = 230/2293.5 = 0.100283 A

Now, according to Ohm’s law, voltage drop across the voltmeter = 1500 × 0.100283 ≈ 150.42V

7 0

4 years ago

Read 2 more answers

Describe at least 1 advantage and 1 disadvantaged to learning about a scientific discovery from

Over [174]

Answer:

Explanation:

You can get alot of info from it then again the info could be misleading

Answer:

Explanation:

You can get some good info from the internet but its most likely the wrong info

Answer:

Explanation:

It informs you with the info you need then again you are most likely getting socialy forced information.

8 0

4 years ago

A circular copper wire is put in tension under a weight of 7000N. What is the ratio of its diameter after and before the load is

zaharov [31]

Answer:

$\frac{d_f}{d} =0.9999983$

Explanation:

Given:

force applied on the copper wire, $F=7000\ N$

cross sectional area of the wire, $a=0.01\ m^2$

Poisson's ratio, $\mu=0.3$

we have, Young's modulus, $E=128\times 10^3\ MPa$

Stress induced due to the applied force:

$\sigma=\frac{F}{a}$

$\sigma=\frac{7000}{0.01}$

$\sigma=700000\ Pa=0.7\ MPa$

Now the longitudinal strain:

$\epsilon=\frac{\sigma}{E}$

$\epsilon=\frac{0.7}{128\times 10^3}$

$\epsilon=5.468\times 10^{-6}$

Now from the relation of Poisson's ratio:

$\mu=\frac{\nu}{\epsilon}$

where:

$\nu=$ lateral strain

$0.3=\frac{\nu}{5.468\times 10^{-6}}$

$\nu=1.6406\times 10^{-6}$ ..................(1)

Now we find the diameter of the wire:

$a=\pi.\frac{d^2}{4}$

$0.01=\pi\times \frac{d^2}{4}$

$\frac{0.04}{\pi} =d^2$

$d=0.1128\ m=112.8\ mm$

When the tensile load is applied its diameter decreases:

The lateral strain is also given as,

$\nu=\frac{\Delta d}{d}$

$1.6406\times 10^{-6}=\frac{\Delta d}{112.8}$

$\Delta d=0.000185\ mm$

Now the final diameter will be:

$d_f=d-\Delta d$

$d_f=112.8-0.000185$

$d_f=112.799815\ mm$

Now the ratio:

$\frac{d_f}{d} =\frac{112.799815}{112.8}$

$\frac{d_f}{d} =0.9999983$

6 0

3 years ago