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hichkok12 [17]
3 years ago
5

1. Strzała o masie 20 g tuż po wystrzale ma prędkość 50 m/s. Oblicz pracę wykonaną

Physics
1 answer:
kow [346]3 years ago
7 0

Answer:

Explanation:

Question 1

An arrow weighing 20g shortly after firing has a speed of 50m / s. Calculate the work done by the athlete. What is the potential energy of the elasticity of the tensed string?

mass m = 20g = 20/1000 = 0.02kg

speed v = 50m / s

P.E = K.E = ½mv²

P.E = ½ × 0.02 × 50²

P.E = 25 J

work done = P.E = 25J

Qestion 2

A 80 kg athlete stood on a trampoline with a coefficient of elasticity of k = 2 kN / m. As far as the edge of the trampoline lowers.

force of elasticity

F = -kx

x = F / k

in our case F will be the force of pressure or gravity

F = mg

g is gravitational acceleration, and according to Newton's second law, acceleration is force through mass - unit of force N, unit of mass kg. Acceleration either in m / s ^ 2 or N / kg

F = 80kg * 10N / kg = 800 N

x = 800N / -2000N = -0.4

The trampoline will lower, so from the level by 0.4 meters and hence this minus

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IrinaVladis [17]

This question involves the concepts of the law of conservation of momentum.

The magnitude of the final momentum of the eight ball is "0.22 N.s".

According to the law of conservation of momentum:

P_{i1}+P_{i2}=P_{f1}+P_{f2}

where,

P_{i1} = initial momentum of the cue ball = 0.23 N.s

P_{i2} = initial momentum of the eight ball = 0 N.s (since ball is initially at rest)

P_{f1} = final momentum of the cue ball = 0.01 N.s

P_{f2} = final momentum of the eight ball = ?

Therefore,

0.23\ N.s + 0\N.s = 0.01\ N.s+P_{f2}\\\\P_{f2} = 0.22\ N.s

Learn more about the law of conservation of momentum here:

brainly.com/question/1113396?referrer=searchResults

3 0
3 years ago
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

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Cv=0.71 KJ/kg.k for air

m=\dfrac{PV}{RT}

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

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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

 

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3 years ago
A battery supplies ________ to the circuit.
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Answer:

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Explanation:

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2 years ago
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