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3 years ago

25. How long does it take a child on a swing to complete one swing if her center of gravity is 4.00 m below the pivot?

Physics

1 answer:

Lina20 [59]3 years ago

4 0

Length=l=4m

$\\ \rm\rightarrowtail T=2\pi\sqrt{\dfrac{l}{g}}$

$\\ \rm\rightarrowtail T=2\pi\sqrt{\dfrac{4}{9.8}}$

$\\ \rm\rightarrowtail T=2\pi(0.63887)$

$\\ \rm\rightarrowtail T=1.27774\pi$

$\\ \rm\rightarrowtail T=4.012s$

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Two large, parallel, conducting plates are 1.00 cm apart and having electric charges of equal magnitudes (80.0 nC/m^2) and oppos

boyakko [2]

(a) 9040 V/m

The magnitude of the electric field between two parallel, oppositely charged plates is given by

$E=\frac{\sigma}{\epsilon_0}$

where

$\sigma$ is the charge surface density on each plate

$\epsilon_0 = 8.85\cdot 10^{-12}$ is the vacuum permittivity

In this problem, the magnitude of the charge density on each plate is

$\sigma = 80.0 nC/m^2 = 80.0\cdot 10^{-9} C/m^2$

Substituting into the formula, we find the magnitude of the electric field:

$E=\frac{80.0\cdot 10^{-9}}{8.85\cdot 10^{-12}}=9040 V/m$

(b) 90.4 V

The electric potential difference between the two plates is given by

$\Delta V=Ed$

where

E is the magnitude of the electric field

d is the separation between the two plates

In this problem, we have

E = 9040 V/m

d = 1.00 cm = 0.01 m

Substituting into the formula, we find

$\Delta V=(9040)(0.01)=90.4 V$

6 0

3 years ago

Can someone help me with these questions pls

gogolik [260]

8. ionic bond because lithium is a metal and oxygen is a non metal.

9. covalent bond because sulfur and oxygen are both non metals.

10. covalent

11. ionic

7 0

3 years ago

Assume that at sea-level the air pressure is 1.0 atm and the air density is 1.3 kg/m3.

scoundrel [369]

Answer

Pressure, P = 1 atm

air density, ρ = 1.3 kg/m³

a) height of the atmosphere when the density is constant

Pressure at sea level = 1 atm = 101300 Pa

we know

P = ρ g h

$h = \dfrac{P}{\rho\ g}$

$h = \dfrac{101300}{1.3\times 9.8}$

h = 7951.33 m

height of the atmosphere will be equal to 7951.33 m

b) when air density decreased linearly to zero.

at x = 0 air density = 0

at x= h ρ_l = ρ_sl

assuming density is zero at x - distance

$\rho_x = \dfrac{\rho_{sl}}{h}\times x$

now, Pressure at depth x

$dP = \rho_x g dx$

$dP = \dfrac{\rho_{sl}}{h}\times x g dx$

integrating both side

$P = g\dfrac{\rho_{sl}}{h}\times \int_0^h x dx$

$P =\dfrac{\rho_{sl}\times g h}{2}$

now,

$h=\dfrac{2P}{\rho_{sl}\times g}$

$h=\dfrac{2\times 101300}{1.3\times 9.8}$

h = 15902.67 m

height of the atmosphere is equal to 15902.67 m.

6 0

3 years ago

How facts differ from theroies?

frez [133]

Answer:

Facts and theories are two different things. In the scientific method, there is a clear distinction between facts, which can be observed and/or measured, and theories, which are scientists' explanations and interpretations of the facts.

Explanation:

3 0

4 years ago

Read 2 more answers

Two objects (38.0 and 17.0 kg) are connected by a massless string that passes over a massless, frictionless pulley. The pulley h

fgiga [73]

Answer:

a) 3.7 m/s^2

b) 231.8 N

Explanation:

Let m1 be mass of the first object (m1 = 38.0 kg) and let m2 be the mass of the second object (m2 = 17.0 kg ). Let a be the acceleration of the two objects. Let F1 be the force of gravity exerted on m1 and F2 be the force of gravity exerted on m2. Let M = m1 +m2

F1 = m1g and F2 = m2g

So Fnet = F1 + F2

Since the pulleys will move in different directions when accelerating...

Fnet = F1 - F2

M×a = m1g - mg2

M×a = g×(m1 -m2)

a = g×(m1 - m2)/M

a = 9.8×(38 - 17)/(38 + 17)

a = 3.7 m/s^2

Looking at the part for m2

Fnet = T - m2g

-m2×a = T - m2g

T = m2(g - a)

T = 231.8 N

7 0

3 years ago