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3 years ago

If the internal energy of a thermodynamic system is increased by 300J while 75J of expansion work is done...?

1 answer:

6 0

U=q+w So this says internal energy is the sum of heat (q) and work (w). Now as you do expansion work, you are losing energy by pushing against your environment so you know that the system is losing 75 joules of work.

Now you can plug those in and solve for your heat. The sign on your heat represents which direction it flowed. Positive means the internal energy rose, so the heat was transferred to the system, negative means it left the system, so energy left the system by heat if that was the case.

300=q-75

<span>Exothermic and endothermic just indicate whether or not heat is leaving or entering the system. So in this case, since q ends up being 375, which is positive, we know that it's endothermic since it absorbed heat.</span>

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A 75-kilogram hockey player is skating across the ice at a speed of 6.0 meters per second. What is the magnitude of the average

saveliy_v [14]

Answer:

(3) 690 N

Explanation:

Force: This is the product of mass and acceleration of a body. The S.I unit of force is Newton(N).

The formula for force is given as,

F = ma..................... Equation 1

Where F = force, m = mass, a = acceleration.

Also,

a = (v-u)/t................... Equation 2

Where v = Final velocity, u = initial velocity, t = time.

Given: u = 6.0 m/s, v = 0 m/s (bring to stop), t = 0.65 s.

Substitute into equation 2

a = (0-6)/0.65

a = -6/0.65

a = -9.23 m/s²

Also given: m = 75 kg

Substitute again into equation 1

F = 75(-9.23)

F = -692.25 N

The negative sign tells that the force oppose the motion of the player

F ≈ 690 N

Hence the right option is (3) 690 N

3 0

4 years ago

A .5 kg air puck moves to the right at 3 m/s, colliding with a 1.5kg air puck that is moving to the left at 1.5 m/s.

arlik [135]

Answer:

part (a) v = 1.7 m/s towards right direction

part (b) Not an elastic collision

part (c) F = -228.6 N towards left.

Explanation:

Given,

Mass of the first puck = $m_1\ =\ 5\ kg$
Mass of the second puck = $m_2\ =\ 3\ kg$
initial velocity of the first puck = $u_1\ =\ 3\ m/s.$
Initial velocity of the second puck = $u_2\ =\ -1.5\ m/s.$

Part (a)

Pucks are stick together after the collision, therefore the final velocities of the pucks are same as v.

From the conservation of linear momentum,

$m_1u_1\ +\ m_2u_2\ =\ (m_1\ +\ m_2)v\\\Rightarrow v\ =\ \dfrac{m_1u_1\ +\ m_2u_2}{m_1\ +\ m_2}\\\Rightarrow v\ =\ \dfrac{5\times 3\ -\ 1.5\times 1.5}{5\ +\ 1.5}\\\Rightarrow v\ =\ 1.7\ m/s.$

Direction of the velocity is towards right due to positive velocity.

part (b)

Given,

Final velocity of the second puck = $v_2\ =\ 2.31\ m/s.$

Let $v_1$ be the final velocity of first puck after the collision.

From the conservation of linear momentum,

$m_1u_1\ +\ m_2u_2\ +\ m_1v_1\ +\ m_2v_2\\\Rightarrow v_1\ =\ \dfrac{m_1u_1\ +\ m_2u_2\ -\ m_2v_2}{m_1}\\\Rightarrow v_1\ =\ \dfrac{5\times 3\ -\ 1.5\times 1.5\ -\ 1.5\times 2.31}{5}\\\Rightarrow v_1\ =\ 1.857\ m/s.$

For elastic collision, the coefficient of restitution should be 1.

From the equation of the restitution,

$v_1\ -\ v_2\ =\ e(u_2\ -\ u_1)\\\Rightarrow e\ =\ \dfrac{v_1\ -\ v_2}{u_2\ -\ u_1}\\\Rightarrow e\ =\ \dfrac{1.857\ -\ 2.31}{-1.5\ -\ 3}\\\Rightarrow e\ =\ 0.1\\$

Therefore the collision is not elastic collision.

part (c)

Given,

Time of impact = t = $25\times 10^{-3}\ sec$

we know that the impulse on an object due to a force is equal to the change in momentum of the object due to the collision,

$\therefore I\ =\ \ m_1v_1\ -\ m_1u_1\\\Rightarrow F\times t\ =\ m_1(v_1\ -\ u_1)\\\Rightarrow F\ =\ \dfrac{m_1(v_1\ -\ u_1)}{t}\\\Rightarrow F\ =\ \dfrac{5\times (1.857\ -\ 3)}{25\times 10^{-3}}\\\Rightarrow F\ =\ -228.6\ N$

Negative sign indicates that the force is towards in the left side of the movement of the first puck.

3 0

3 years ago

_________ light is unique in that it vibrates mostly in one direction.

Misha Larkins [42]

Polarized light light is unique in that it vibrates mostly in one direction.

Polarized mild waves are light waves in which the vibrations occur in a single plane. The process of reworking unpolarized light into polarized light is called polarization. There are a ramification of methods of polarizing mild.

Polarization is used for differentiating among transverse and longitudinal waves. Infrared spectroscopy makes use of polarization. it is used in seismology to take a look at earthquakes. In Chemistry, the chirality of organic compounds is tested the use of polarization strategies.

Refraction is the change in route of waves that takes place when waves tour from one medium to every other. . Light has a dual nature. as it has waves, sunlight passing via rainstorm makes a rainbow. however, while mild moves a sun mobile, it can provide strength as a series of very small bursts. particles of count number have names together with the proton, electron and neutron.

Learn more about lights here:-brainly.com/question/19697218

#SPJ4

6 0

2 years ago

The time period T of a simple pendulum is given by the relation

Vanyuwa [196]

Answer:

$T^2 \propto L$

Explanation:

The period of a simple pendulum is given by:

$T=2\pi \sqrt{\frac{L}{g}}$

where

L is the length of the pendulum

g is the acceleration of gravity

From this equation we can write

$T\propto \sqrt{L}\\T\propto \frac{1}{\sqrt{g}}$

Taking the square of this equation, we get:

$T^2 = (2\pi)^2 \frac{L}{g}$

So we see that $T^2$ is proportional to L and inversely proportional to g. So, we can write:

$T^2 \propto L\\T^2 \propto \frac{1}{g}$

So the only correct option is

$T^2 \propto L$

5 0

4 years ago

Read 2 more answers

Because quantum mechanics is physics that describes the interactions of very small objects (i.e. molecules, atoms, and electrons

stira [4]

Ha! Lot of words but the question itself is easy.
The answer is 2.5 times 10 to the 5th power.
The main part of the numbers has the decimal point placed after the first digit.
Then for what number of power, you just count the number of decimal places moved.
I hope this helps you.

5 0

3 years ago

Read 2 more answers