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3 years ago

Question 2 of 25

Physics

1 answer:

True [87]3 years ago

5 0

Answer: The symbol representing the result of a gas expanding against a constant pressure is W

Explanation:

According to first law of thermodynamics, energy can neither be destroyed nor created but rather transferred to one place to another and converted to and from other energy forms.

The mathematical form of first law of thermodynamics is:

$\Delta U=q+W$

where $\Delta U$ = change in internal energy

q = heat absorbed or released

W = work $(W= P\Delta V)$

P = pressure

$\Delta V$ = volume change

Thus the changes in heat or work leads to change in internal energy.

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Sally is on a canoe that comes to a stop a small distance from the dock. Since it is such a small distance, Sally decides to jum

natita [175]

Answer:

v₂> v₃ velocity canoe is more than velocity fishing boat

Explanation:

For this exercise we must define a system consisting of the girl, Sally and the boat, in one case the canoe and in the other the fishing boat; for this system we can use moment conservation

Initial moment. Before the jump

p₀ = (M + m₂) v

Final moment. After the jump

$p_{f}$ = M v₁ - m₂ v₂

Where m and v are the masses and speed of the canoe

p₀ = p_{f}

(M + m₂) v = M v₁ - m₂ v₂

In the case of changing the canoe for the heaviest fishing boat, the final moment is

p_{f} = M v₁ - m₃ v₃

p₀ = p_{f}

(M + m₃) v = M v₁ - m₃ v₃

Since the canoe is stopped the speed v = 0, we write the speed of each boat

Canoe

0 = M v₁ - m₂ v₂

v₂ = M / m₂ v₁

Fishing boat

0 = M v₁ - m₃ v₃

v₃ = M / m₃ v₁

Since the masses of the fishing boat (m₃) is greater than the mass of the canoe (m₂) the speed of the fishing boat is less than the speed of the canoe, we can find the relationship between the two speeds

v₂ / v₃ = m₃ / m₂

Here you can see what v₂> v₃ velocity canoe is more than velocity fishing boat

8 0

3 years ago

A student at the top of building of height h throws one ball upward with the initial speed V and then throws a second ball downw

Vlad1618 [11]

Answer:

They are the same (assuming there is no air friction)

Explanation:

Take a look at the picture.

When the first ball (the one thrown upward) gets to the point marked as A, the speed will has the exact same value V but the velocity will now point downward (just like the second ball).

So if you think about it, the first ball, from point A to the ground, will behave exactly like the second ball (same initial speed, same height).

That is why the speeds will be the same when they reach the ground.