All categories

3 years ago

Which statement best describes the law of conservation of energy?

Physics

2 answers:

shtirl [24]3 years ago

7 0

Answer:

b!!!! did it help? :)))

Lubov Fominskaja [6]3 years ago

3 0

B. Energy cannot be created or destroyed, but it can change into different forms.

You might be interested in

Air contained in a rigid, insulated tank fitted with a paddle wheel, initially at 300 K, 2 bar, and a volume of 3 m3, is stirred

madam [21]

Answer:

a)P₂ =4 bar

b)W= - 1482.48 KJ

It means that work done on the system.

c)S₂ - S₁ = 3.42 KJ/K

Explanation:

Given that

T₁ = 300 K ,V₁ = 3 m³ ,P₁=2 bar

T₂ = 600 K ,V₂=V₁ 3 m³

Given that tank is rigid and insulated.It means that volume of the gas will remain constant.

Lets take the final pressure = P₂

For ideal gas P V = m R T

$\dfrac{P_2}{P_1}=\dfrac{T_2}{T_1}$

$P_2=\dfrac{T_2}{T_1}\times P_1$

$P_2=\dfrac{600}{300}\times 2$

P₂ =4 bar

Internal energy

ΔU = m Cv ΔT

Cv=0.71 KJ/kg.k for air

$m=\dfrac{PV}{RT}$

$m=\dfrac{200\times 3}{0.287\times 300}\ kg$

m= 6.96 kg

ΔU= 6.96 x 0.71 x (600 - 300)

ΔU=1482.48 KJ

From first law

Q= ΔU + W

Q= 0 Insulated

W = - ΔU

W= - 1482.48 KJ

It means that work done on the system.

Change in the entropy

$S_2-S_1=mC_v\ \ln\dfrac{T_2}{T_1}$

$S_2-S_1=6.96\times 0.71\ \ln\dfrac{600}{300}$

S₂ - S₁ = 3.42 KJ/K

5 0

3 years ago

Two 5 kg potted cacti, one in a black pot and one in a blue pot, slide down a sagging shelf in the same direction with

svp [43]

Answer:

Answers A and D are the correct solution.

Explanation:

Both pots have the same mass and the same velocity vector.

the only difference between A and D is the selection of the reference frame positive direction.

5 0

3 years ago

True or false? If two components are connected in series, the current through one component will

Molodets [167]

the answer is ( True ) .

the current is the same in series circuits .

8 0

3 years ago

SOMEONE PLEEEAASSEE HELP ME T.T . This is due today! 40 points!!! I need to know how to find the x-axis.

Leviafan [203]

Answer:

GET NOOBED BEECH

Explanation:

asfasdfasdfasdfasdfasdf

6 0

3 years ago

What is the mass of an object that has a weight of 110N ?

fgiga [73]

Weight (W) = 110 N
Acceleration due to gravity (g) = 9.8 m/s^2
Let the mass of the object be m.
By using the formula, W = mg, we get,
110 N = 9.8 m/s^2 × m
or, m = 110 N ÷ 9.8 m/s^2
or, m = 11.2 Kg

Answer:

The mass of the object is 11.2 Kg.

Hope you could get an idea from here.

Doubt clarification - use comment section.

3 0

3 years ago