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3 years ago

17. A skateboard has a mass of 3.2 kg. If it slips out from a skateboarder and has

Physics

1 answer:

Akimi4 [234]3 years ago

6 0

<h2>Book will hit the foot with force 21.8 N</h2>

Explanation:

The momentum of any object = m v

here m is the mass of body and v is its velocity

Thus momentum P = 3.2 x 1 = 3.2 kg-m

As the book is falling freely , so it will fall with and acceleration g

The force exerted by it is = m g

Thus force = 2.18 x 10 = 21.8 N

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The human ear canal is about 2.6 cm long and can be regarded as a tube open at one end and closed at the eardrum. What is the fu

Ugo [173]

Answer:

f = v/λ

= v/4*L

= 343 / 4 (0.026)

= 3120 Hz

8 0

3 years ago

Read 2 more answers

"A steel rotating-beam test specimen has an ultimate strength of 120 kpsi. Estimate the life of the specimen if it is tested at

MrRissso [65]

Answer:

life (N) of the specimen is 117000 cycles

Explanation:

given data

ultimate strength Su = 120 kpsi

stress amplitude σa = 70 kpsi

solution

we first calculate the endurance limit of specimen Se i.e

Se = 0.5× Su .............1

Se = 0.5 × 120

Se = 60 kpsi

and we know strength of friction f = 0.82

and we take endurance limit Se is = 60 kpsi

so here coefficient value (a) will be

a = $\frac{(f\times Su)^2}{Se}$ ......................1

put here value and we get

a = $\frac{(0.82\times 120)^2}{60}$

a = 161.4 kpsi

so coefficient value (b) will be

b = $-\frac{1}{3}log\frac{(f\times Su)}{Se}$

b = $-\frac{1}{3}log\frac{(0.82\times 120)}{60}$

b = −0.0716

so here number of cycle N will be

N = $(\frac{ \sigma a}{a})^{1/b}$

put here value and we get

N = $(\frac{ 70}{161.4})^{1/-0.0716}$

N = 117000

so life (N) of the specimen is 117000 cycles

7 0

3 years ago

Raul dug a hole in his yard to repair a water pipe. It took him 2 seconds to apply a force of 50 Newtons to push the shovel 0.25

Sergeu [11.5K]

Answer:

Option B. 6.25 J/S

Explanation:

Data obtained from the question include:

t (time) = 2secs

F (force) = 50N

d (distance) = 0.25m

P (power) =?

The power can be obtained by using the formula P = workdone/time.

P = workdone / time

P = (50 x 0.25)/ 2

P = 6.25J/s

3 0

3 years ago

12345 [234]

The similarity is that they both are types of bonds in molecules.
Ionic bonds are between a metal and a nonmetal.
Covalent bonds are between two nonmetals.

8 0

3 years ago

Weak magnetic fields can be measured at the surface of the brain. Although the currents causing these fields are quite complicat

STALIN [3.7K]

To develop this problem it is necessary to apply the concepts related to a magnetic field in spheres.

By definition we know that the magnetic field in a sphere can be described as

$B = \frac{\mu_0}{2}\frac{Ia^2}{(z^2+a^2)^{3/2}}$

Where,

a = Radius

z = Distance to the magnetic field

I = Current

$\mu_0 =$ Permeability constant in free space

Our values are given as

$D=2a = 16cm \rightarrow$ diameter of the sphere then,

$a = 0.08m$

Thus z = a

$B = \frac{\mu_0}{2}\frac{Ia^2}{(a^2+a^2)^{3/2}}$

$B = \frac{\mu_0I}{2(2^{3/2})a}$

$B = \frac{\mu_0 I}{2^{5/2}a}$

Re-arrange to find I,

$I = \frac{2^{5/2}Ba}{\mu_0}$

$I = \frac{2^{5/2}(3*10^{-12})(8*10^{-2})}{4\pi*10^{-7}}$

$I = 1.08*10^{-6}A$

Therefore the current at the pole of this sphere is $1.08*10^{-6}A$

5 0

3 years ago