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anyanavicka [17]
3 years ago
11

Explain how a thumbtack is designed so that you do not have to use a lot of force to push it through paper or the surface of a b

ulletin board?
Physics
1 answer:
Brums [2.3K]3 years ago
8 0
Thumbtacks have a flat top which gives you a bigger area to push on, and the end is tapered and sharp to make it easier to push it into a wall, etc.
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A 50-loop circular coil has a radius of 3 cm. It is oriented so that the field lines of a magnetic field are perpendicular to th
nikitadnepr [17]

Answer:

-17.8 V

Explanation:

The induced emf in a coil is given as:

E = \frac{-NdB\pi r^2}{dt}

where N = number of loops

dB = change in magnetic field

r = radius of coil

dt = elapsed time

From the question:

N = 50

dB = final magnetic field - initial magnetic field

dB = 0.35 - 0.10 = 0.25 T

r = 3 cm

dt = 2 ms = 0.002 secs

Therefore, the induced emf is:

E = \frac{-50 * 0.25 * \pi * 0.03^2}{0.002} \\E = -17.8 V

Note: The negative sign implies that the EMf acts in an opposite direction to the change in magnetic flux.

6 0
4 years ago
Can someone help me answer this??
Bingel [31]

Answer:

<h2>3,2 oky na dekh Lena ek bar</h2><h2>2,5</h2>
7 0
3 years ago
Samples of different materials, A and B, have the same mass, but the sample
Effectus [21]

Answer:

B. The particles that make up material B have more mass than the

particles that make up material A.

Explanation:

3 0
3 years ago
The period of a wave is 20 ms (milliseconds) and its wavelength is 4 cm. Calculate:
IgorLugansk [536]

Answer:

A. 50 Hz

B. 2 m/s

Explanation:

We'll begin by converting 20 ms to s. This can be obtained as follow:

1000 ms = 1 s

Therefore,

20 ms = 20 ms × 1 s / 1000 ms

20 ms = 0.02 s

Next, we shall convert the value of the wavelength (i.e 4cm) to m. This can be obtained as follow:

100 cm = 1 m

Therefore,

4 cm = 4 cm × 1 m / 100 cm

4 cm = 0.04 m

A. Determination of the frequency.

Period (T) = 0.02 s

Frequency (f) =?

f = 1 / T

f = 1 / 0.02

f = 50 Hz

Therefore, the frequency of the wave is 50 Hz

B. Determination of the velocity.

Wavelength (λ) = 0.04 m

Frequency (f) = 50 Hz

Velocity (v) =?

v = λf

V = 0.04 × 50

v = 2 m/s

Therefore, the velocity of the wave is 2 m/s

8 0
3 years ago
A pulley system is used at a dock to lift shipments of fish off a boat. If you apply a force of 100 N to the pulley, it pulls th
labwork [276]

Explanation:

a. Mechanical advantage = force out / force in

MA = 830 / 100

MA = 8.3

b. Efficiency = work out / work in

0.80 = W / 600 J

W = 480 J

7 0
3 years ago
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