List two examples of when you would use light years as a measurement.

The temperature of water in a beaker is 45°C. What does this measurement represent?

Tasya [4]

Answer:

the average kinetic energy of water particles - C.

8 0

3 years ago

Why do you not come to thermal equilibrium on a cold day

Tju [1.3M]

Two physical systems are in thermal equilibrium if no heat flows between them when they are connected by a path permeable to heat. Thermal equilibrium obeys the zeroth law of thermodynamics. A system is said to be in thermal equilibrium with itself if the temperature within the system is spatially and temporally uniform.

Systems in thermodynamic equilibrium are always in thermal equilibrium, but the converse is not always true. If the connection between the systems allows transfer of energy as heat but does not allow transfer of matter or transfer of energy as work, the two systems may reach thermal equilibrium without reaching thermodynamic equilibrium.

3 0

3 years ago

A bolt is dropped from a bridge under construction, falling 96 m to the valley below the bridge. (a) How much time does it take

irakobra [83]

Answer:

a)It takes the bolt 0.25 s to pass the last 11% of the fall.

b)When the bolt begins to fall the last 11% of the fall its velocity is -41.2 m/s.

c)The velocity of the bolt just before it reaches the ground is -43.6 m/s

Explanation:

Hi there!

a) Let´s calculate how much distance it is the last 11% of the fall:

96 m · 0.11 = 10.56 m

So, we have to find how much time it takes the bolt to pass from a height of 10.56 m to the ground.

First, let´s calculate how much time it takes the bolt to reach a height of 10.56 m. For that we can use this equation:

h = h0 + v0 · t + 1/2 · g · t²

Where:

h = height of the bolt at a time t.

h0 = initial height.

v0 = initial velocity.

t = time.

g = acceleration due to gravity.

If we consider the ground as the origin of the frame of reference, then h0 = 96 m. Since the bolt is dropped, the initial velocity is zero (v0 = 0). Then, the equation gets reduce to this:

h = h0 + 1/2 · g · t²

We have to find at which time h = 10.56 m.

10.56 m = 96 m - 1/2 · 9.8 m/s² · t²

Solving for t:

√(-2 · (10.56 m - 96 m) / 9.8 m/s²) = t

t = 4.2 s

Now that we have the time at which the bolt is located at 10.56 m above the ground, we can calculate the velocity of the bolt at that time.

The equation of velocity (v) of the bolt is the following:

v = v0 + g · t

at t = 4.2 s.

v = 0 - 9.8 m/s² · 4.2 s

v = -41.2 m/s

When the bolt begins to fall the last 11% of the fall its velocity is -41.2 m/s.

Now, we can calculate how much time it takes to fall the last 10.56 m.

The initial velocity of the bolt will be the velocity at h = 10.56 m. The initial height will be 10.56 m.

h = h0 + v0 · t + 1/2 · g · t²

We have to find the time at which h = 0 (the bolt hits the ground)

0 = 10.56 m - 41.2 m/s · t - 1/2 · 9.8 m/s² · t²

Solving the quadratic equation using the quadratic formula:

t = 0.25 s (the other solution of the quadratic equation is negative and thus discarded).

It takes the bolt 0.25 s to pass the last 11% of the fall.

Now, let´s calculate the velocity of the bolt when it reaches the ground:

v = v0 + g · t

v = -41.2 m/s - 9.8 m/s² · 0.25 s

v = -43.6 m/s

The velocity of the bolt just before it reaches the bolt is -43.6 m/s

6 0

3 years ago

Physics question i appreciate your help please

den301095 [7]

Solution: From the given question, we shall find the vector quantity among the

(A) Time , (B) Velocity, (C) Distance , (D) Speed

Concept: Vector Quantity: All those physical quantities which have magnitude as well as specific directions, are called Vector Quantities.

Here, Time, Distance and Speed have only magnitude but have no directions so they will be scalar quantities.

Now, Velocity: It is defined as the change in displacement per unit time. Since the change in the displacement will be in particular direction only. Hence, velocity will be the vector quantity.

Hence, the option (B) Velocity will be the correct option.

4 0

3 years ago

Why aren't homes wired in series? A. Because it's too expensive. B. Parallel circuits are too complex for home wiring. O C. Beca

Liula [17]

Answer:

D. If a home were wired in series, every light and appliance would have to be turned on in order for any light or appliance to work.

Explanation:

In a series circuit, all the appliances are connected on the same branch of the circuit, one after the other. This means that the current flowing throught them is the same. However, this means also that if one of the appliance is turned off (so, its switch is open), that appliance breaks the circuit, so the current can no longer flow through the other appliances either.

On the contrary, when the appliances are connected in parallel, they are connected in different branches, so if one of them is switched off, the other branches continue working unaffacted by it.

6 0

3 years ago

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