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3 years ago

14

Urgent!!!! Timed quiz. Calculate the velocity of the pink car.

1 answer:

dem82 [27]3 years ago

3 0

Answer:

Option A

20 m/s

Explanation:

From the law of conservation of linear momentum, the sum of momentum before and after collision equals zero hence for this case also, the sum of momentum of the two cars before collision should be equal to momentum after collision.

Momentum is given as the product of mass and velocity, where velocity considers the direction. Momentum, p=mv where m is the mass of the object and v is the velocity.

Momentum before collision

Since the velocities of both cars before collision are zero hence their momentum are zero ie 0.5*0+(1*0)=0

Momentum after collision

For 0.5 Kg car, its momentum will be 0.5*-40=-20 Kg.m/s

For the 1 kg car its momentum will be 1*v=1v

v-20=0

v=20 m/s

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Suppose that we use a heater to boil liquid nitrogen (N2 molecules). 4480 J of heat turns 20 g of liquid nitrogen into gas. Note

love history [14]

Answer:

The energy is $9.4\times10^{-21}\ J$

(a) is correct option

Explanation:

Given that,

Energy = 4480 j

Weight of nitrogen = 20 g

Boil temperature = 77 K

Pressure = 1 atm

We need to calculate the internal energy

Using first law of thermodynamics

$Q=\Delta U+W$

$Q=\Delta U+nRT$

Put the value into the formula

$4480=\Delta U+\dfrac{20}{28}\times8.314\times77$

$\Delta U=4480-\dfrac{20}{28}\times8.314\times77$

$\Delta U=4022.73\ J$

We need to calculate the number of molecules in 20 g N₂

Using formula of number of molecules

$N=n\times \text{Avogadro number}$

Put the value into the formula

$N=\dfrac{20}{28}\times6.02\times10^{23}$

$N=4.3\times10^{23}$

We need to calculate the energy

Using formula of energy

$E=\dfrac{\Delta U}{N}$

Put the value into the formula

$E=\dfrac{4022.73}{4.3\times10^{23}}$

$E=9.4\times10^{-21}\ J$

Hence, The energy is $9.4\times10^{-21}\ J$

4 0

2 years ago

Considerando que los coeficientes de dilatación de los siguientes metales son: hierro 11.7 x 10-6; plomo 27.3 x 10-6; cobre 16.7

Rasek [7]

Answer:

el plomo será el más largo

Explanation:

Dado que;

longitud inicial (l1) = 4m

Longitud final l2

aumento de temperatura (θ) = 10 ° C

Coeficiente de expansión lineal α

Ahora para el hierro;

α = 11,7 x 10-6

Desde;

l2-l / l1θ = α

l2 = α l1θ + l1

l2 = l1 (αθ + 1)

l2 = 4 ((11,7 x 10-6 * 10) + 1)

l2 = 4.00044 m

Para el plomo

l2 = 4 ((27,3 x 10-6 * 10) + 1)

l2 = 4,00109 m

Para cobre

l2 = 4 ((16,7 x 10-6 * 10) + 1)

l2 = 4.000668 m

Por lo tanto, el plomo será el más largo

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2 years ago

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Answer:pelo o que eu sei é ..

V

V

V

F

F

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3 years ago

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2 years ago

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2 years ago

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