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3 years ago

What do you think happened to the energy you transferred to the notebook when you pushed it?

Physics

2 answers:

xeze [42]3 years ago

8 0

Answer:

It got transferred to kinetic energy

Explanation:

Scorpion4ik [409]3 years ago

7 0

Answer:

The energy changed from kinetic energy to heat energy. Friction causes heating.

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A piano string having a mass per unit length equal to 4.70 10-3 kg/m is under a tension of 1 400 N. Find the speed with which a

sweet [91]

Answer:

The speed of the sound wave on the string is 545.78 m/s.

Explanation:

Given;

mass per unit length of the string, μ = 4.7 x 10⁻³ kg/m

tension of the string, T = 1400 N

The speed of the sound wave on the string is given by;

$v = \sqrt{\frac{T}{\mu} }$

where;

v is the speed of the sound wave on the string

Substitute the given values and solve for speed,v,

$v = \sqrt{\frac{T}{\mu} }\\\\v = \sqrt{\frac{1400}{4.7*10^{-3}} }\\\\v = \sqrt{297872.34}\\\\v = 545.78 \ m/s$

Therefore, the speed of the sound wave on the string is 545.78 m/s.

3 0

3 years ago

A box is held at rest by two ropes that form 30° angles with the vertical. The tension T in either rope is 42 N. What is the wei

iragen [17]

<h3><u>Answer;</u></h3>

= 73 N

<h3><u>Explanation</u>;</h3>

Using the formula

2 T cos(30°) = w

Where; T is the tension on each string, while w is the weight of the box given by mg

Therefore;

W = 2Tcos 30°

= 2 × 42 cos 30°

= 84 cos 30°

= 72.74

7 0

4 years ago

Air is compressed adiabatically in a piston-cylinder assembly from 1 bar, 300 K to 10 bar, 600 K. The air can be modeled as an i

julia-pushkina [17]

Answer:

1) the entropy generated is Δs= 0.0363 kJ/kg K

2) the minimum theoretical work is w piston = 201.219 kJ/kg

Explanation:

1) From the second law of thermodynamics applied to an ideal gas

ΔS = Cp* ln ( T₂/T₁) - R ln (P₂/P₁)

and also

k= Cp/Cv , Cp-Cv=R → Cp*( 1-1/k) = R → Cp= R/(1-1/k)= k*R/(k-1)

ΔS = k*R/(k-1)* ln ( T₂/T₁) - R ln (P₂/P₁)

where R= ideal gas constant , k= adiabatic coefficient of air = 1.4

replacing values (k=1.4)

ΔS = k*R/(k-1)* ln ( T₂/T₁) - R ln (P₂/P₁)

ΔS = 1.4/(1.4-1) *8.314 J/mol K * ln( 600K/300K) - 8.314 J/mol K * ln (10 bar/ 1bar)

ΔS = 1.026 J/ mol K

per mass

Δs = ΔS / M

where M= molecular weight of air

Δs = 1.026 J/ mol K / 28.84 gr/mol = 0.0363 J/gr K = 0.0363 kJ/kg K

2) The minimum theoretical work input is carried out under a reversible process. from the second law of thermodynamics

ΔS =∫dQ/T =0 since Q=0→dQ=0

then

0 = k*R/(k-1)* ln ( T₂/T₁) - R ln (P₂/P₁)

T₂/T₁ = (P₂/P₁)^[(k-1)/k]

T₂ = T₁ * (P₂/P₁)^[(k-1)/k]

replacing values

T₂ = 300K * ( 10 bar/1 bar)^[0.4/1.4] = 579.2 K

then from the first law of thermodynamics

ΔU= Q - Wgas = Q + Wpiston ,

where ΔU= variation of internal energy , Wgas = work done by the gas to the piston , Wpiston = work done by the piston to the gas

since Q=0

Wpiston = ΔU

for an ideal gas

ΔU= n*Cv*(T final - T initial)

and also

k= Cp/Cv , Cp-Cv=R → Cv*( k-1) = R → Cv= R/(k-1)

then

ΔU= n*R/(k-1)*(T₂ - T₁)

W piston = ΔU = n*R/(k-1)*(T₂ - T₁)

the work per kilogram of air will be

w piston = W piston / m = n/m*R/(k-1)*(T₂ - T₁) = (1/M*) R/(k-1)*(T₂ - T₁) ,

replacing values

w piston = (1/M*) R/(k-1)*(T₂ - T₁) = 1/ (28.84 gr/mol)* 8.314 J/mol K /0.4 * ( 579.2 K - 300 K) = 201.219 J/gr = 201.219 kJ/kg

6 0

3 years ago

A car moving south speeds up from 10m/s to 40m/s in 15 seconds what is the cars acceleration

torisob [31]

The acceleration of the car will be 2m/s².Option A is correct. According to Newton's second law, the eventual effect of all forces applied to a body is its acceleration.

<h3>What is acceleration?</h3>

The rate of change of velocity with respect to time is known as acceleration.

Given data;

Initial velocity,u=10m/s

Final velocity,v=40m/s

Time elapsed,t=15 seconds

To find ;

Acceleration, a

The acceleration when the change in the velocity is observed by the formula as:

$\rm a= \frac{v-u}{t}$

Substitute the given values:

$\rm a= \frac{40-10}{15} \\\\ a=\frac{30}{15} \\\\ a=2 \ m/s^2$

The car's acceleration will be 2 m/s².

Hence, option A is correct.

To learn more about acceleration, refer to the link;

brainly.com/question/2437624

#SPJ1

8 0

2 years ago

Which reaction connects the citric acid cycle to the electron‑transport chain and amino acid synthesis?

Tanya [424]

Conversion of succinylcoA to succinate is the reaction that link acid cycle to the electron‑transport chain and amino acid synthesis.

<h3>Conversion of succinylcoA to succinate</h3>

SuccinylCoA is converted into succinate through the hydrolytic release of coenzyme A by succinyl-CoA synthetase Also succinyl-CoA is porphyrin synthesis, where it combine with glycine by ALA synthase to form δ-aminolevulinic acid.

Succinyl CoA is catalytically converted to succinate. The enzyme stimulates the hydrolysis of succinyl CoA into succinate and ATP and this represents a remarkable point of substrate level phosphorylation. After this, it link up to the electron transport chain via citric acid cycle.

Therefore, Conversion of succinylcoA to succinate is the reaction that link citric acid cycle to the electron‑transport chain and amino acid synthesis.

Learn more about Citric acid cycle conversion here.

brainly.com/question/11238674

7 0

2 years ago