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3 years ago

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Physics

1 answer:

sveta [45]3 years ago

4 0

Answer:

A thermally insulated vessel contains

150 g of water at 0°C. Then the air from the

vessel is pumped out adiabatically. A

fraction of water turns into ice and the rest

evaporates at 0°C itself. The mass of

evaporated water will be closest to:

(Latent heat of vaporization of

water = 2.10 x 106 Jkg - and Latent heat of

Fusion of water = 3.36 x 105J kg-1)

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Jumping up before the elevator hits. After the cable snaps and the safety system fails, an elevator cab free-falls from a height

noname [10]

Answer:

a) I = 2279.5 N s , b) F = 3.80 10⁵ N, c) I = 3125.5 N s and d) F = 5.21 10⁵ N

Explanation:

The impulse is equal to the variation in the amount of movement.

I =∫ F dt = Δp

I = m $v_{f}$ - m v₀

Let's calculate the final speed using kinematics, as the cable breaks the initial speed is zero

$v_{f}$ ² = V₀² - 2g y

$v_{f}$ ² = 0 - 2 9.8 30.0

$v_{f}$ = √588

$v_{f}$ = 24.25 m/s

a) We calculate the impulse

I = 94 24.25 - 0

I = 2279.5 N s

b) Let's join the other expression of the impulse to calculate the average force

I = F t

F = I / t

F = 2279.5 / 6 10⁻³

F = 3.80 10⁵ N

just before the crash the passenger jumps up with v = 8 m / s, let's take the moments of interest just when the elevator arrives with a speed of 24.25m/s down and as an end point the jump up to vf = 8 m / n

c) I = m $v_{f}$ - m v₀

I = 94 8 - 94 (-24.25)

I = 3125.5 N s

d) F = I / t

F = 3125.5 / 6 10⁻³

F = 5.21 10⁵ N

7 0

3 years ago

When an electron in a certain excited energy level in a one-dimensional box of length 2.00 Å makes a transition to the ground st

Fiesta28 [93]

Answer:

Calculate the wavelength associated with an electron with energy 2000 eV.

Sol: E = 2000 eV = 2000 × 1.6 × 10–19 J

5 0

3 years ago

A cylindrical wire made of an unknown alloy hangs from a support in the ceiling. You measure the relaxed length of the wire to b

IceJOKER [234]

Answer: hello some of your values are wrongly written hence I will resolve your question using the right values

answer:

stiffness = 1.09 * 10^-6 N/m

Explanation:

Given data:

Length ( l ) = 16 m

radius of wire ( r ) = 3.5 m

mass ( m ) = 5kg

<u>Distance stretched ( Δl ) = 4 * 10^-3 m </u> ( right value )

<u>average bond length ( between atoms ) = 2.3 * 10^-10 m </u>( right value)

first step : calculate the area

area ( A ) = πr^2 = π * ( 3.5)^2 = 38.48 m^2

γ = MgL / A Δl

= [ (5 * 9.81 * 16 ) / ( 38.48 * (4.3*10^-3) ) ]

= 784.8 / 0.165 = 4756.36 N/m^2

hence : stiffness = γ * bond length

= 4756.36 * 2.3 * 10^-10 = 1.09 * 10^-6 N/m

8 0

3 years ago

Which muscles help you sit up from laying down?

rosijanka [135]

Answer: abdominal muscles.

Explanation:

3 0

3 years ago

Read 2 more answers

Give a simple explanation why the pressure changes by this factor.Word Bank:1. two2.greater3.smaller4.four5.eightDoubling the sp

diamong [38]

Answer

speed of the molecules

s₁ = v t

when velocity is doubled

s₂ = (2 v)t

= 2 s₁

they will hit the wall of container two times as often.

the momentum of molecule

p₁ = mvr

p₂ = m(2v)r = 2(mvr)

= 2 p₁

the momentum change is two times as great.

force is change in momentum

Δp = F(Δt)

mv-(-mv) = 2 mv

$F = \dfrac{2 mv}{\Delta t}$

F α v

therefore average force impart to the wall on each collision is two times

$p = \dfrac{F_{total}}{A}$

$p = \dfrac{Nmv^2}{3LA}$

p α v²

here the velocity is doubled it means pressure becomes four times.

6 0

3 years ago