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3 years ago

If two objects are in thermal equilibrium, do they have the same thermal or internal energy?

Physics

1 answer:

Tpy6a [65]3 years ago

7 0

Answer:

Yes, they do have the same internal energy.

Explanation:

The thermal balance refers to when there is no heat transfer between the bodies and their surroundings i.e. the bodies and the environment are at the same temperature.

Suppose two bodies of different masses and different materials, each one of them is at a temperature of 25(° C), which is the same temperature as the temperature of the environment, if these two bodies are close to each other, there is also heat transfer as they are at the same temperature, in the absence of any type of energy that enter or exit in these bodies, the amount of internal energy will be equal in both bodies.

Note: when the internal energy of one of these bodies is increased, heat transfer will happen, always looking for the thermal balance.

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3) A driver in a 1000-kg car traveling at 24 m/s slams on the brakes and skids to a stop. If the coefticient of friction between

Natali5045456 [20]

Answer:

A) 37 m

Explanation:

The car is moving of uniformly accelerated motion, so the distance it covers can be calculated by using the following SUVAT equation:

$v^2 -u^2 = 2ad$ (1)

where

v = 0 m/s is the final velocity of the car

u = 24 m/s is the initial velocity

a is the acceleration

d is the length of the skid

We need to find the acceleration first. We know that the force responsible for the (de)celeration is the force of friction, so:

$F=ma=-\mu mg$

where

m = 1000 kg is the mass of the car

$\mu = 0.80$ is the coefficient of friction

a is the deceleration of the car

g = 9.8 m/s^2 is the acceleration due to gravity

The negative sign is due to the fact that the force of friction is against the motion of the car, so the sign of the acceleration will be negative because the car is slowing down. From this equation, we find:

$a=-\mu g$

And we can substitute it into eq.(1) to find d:

$v^2 -u^2 = 2(\-mu g) d\\d= \frac{v^2-u^2}{-2 \mu g}=\frac{0-(24 m/s)^2}{-2(0.80)(9.8 m/s^2)}=36.7 m \sim 37 m$

7 0

4 years ago

The inner transition metals include the

Sedbober [7]

Answer: They include elements 57-71, or lanthanides, and 89-103, or actinides. ... Inner transition metals have three incomplete outermost electron shells and are all metals.

3 0

3 years ago

The material through which a mechanical wave travels is a.a medium.b.empty space.c.ether.d.air

Elza [17]

<h2>Answer: Medium </h2>

The medium is the main factor that differentiates a mechanical wave from an electromagnetic wave, since the first can not propagate without its existence, while the second can propagate regardless of whether the medium exists or not.

In addition, it is the medium that will define, the propagation speed of the wave, according to its specific physical characteristics.

Therefore, the <u>correct answer</u> is a.

5 0

3 years ago

describe the physics modeling process in moving a basketball and say what effects you should overlook

Dahasolnce [82]

Answer:ui9i

Explanation:

jiooooooooooooo

7 0

3 years ago

The gas tank is made from A-36 steel and has an inner diameter of 1.50 m. If the tank is designed to withstand a pressure of 5 M

Tanzania [10]

Answer:

a. t = 23mm, b. t = 20mm

Explanation:

Obtain the value of yield strength in tension for A- 36 steel from table ‘Average Mechanical Properties of typical Engineering Materials’, which is σ(y) = 250 MPa.

Assume that the thin wall analysis is valid, Calculate the hoop stress

σ(1) = pd/2t, where p is the pressure in the tank, d is the internal diameter of the tank and t is the thickness.

Substitute 5MPa for p and 1.5m for d

σ(1) = 5 x 10⁶x 1.5/2t

σ(1) = (3.75 x 10⁶)/t

Calculate the longitudinal stress

σ(2) = pd/4t

σ(2) = (5 x 10⁶ x 1.5)/4t

Apply Maximum Shear stress theory which states that failure occurs when the maximum shear stress from a combination of principal stresses <u>equals or exceeds</u> the value obtained for the shear stress at yielding in the uni-axial tensile test. Hence

τ(abs.max) ≤ τ (allowed)

τ (abs.max) ≤ σy /2FS, where FS is the factor of safety

Substitute σ(1)/2 for τ (abs.max) as both the principal stresses have same sign.

σ(1)/2 ≤ σy/2FS

3.75 x 10⁶/2t = 250 x 10⁶/2 x 1.5

T = 0.0225m = 22.5mm = 23mm to the nearest millimeter

Hence the required minimum thickness using the maximum shear stress theory is t = 23mm

Apply maximum distortion energy theorem

σ²(allowed) =σ²(1) – σ(1) x σ(2) + σ²(2)

σ²(y)(allowed)/FS = (3.75 x 10⁶/t)² – (3.75 x 10⁶/t) x (1.875 x 10⁶/t) + (1.875 x 106/t)²

250 x 10⁶/1.5 = (3.2476 x 10⁶)/t

t = 3.2476/166.67

t = 0.0195 m = 19.50 mm = 20mm to the nearest millimeter

Hence, the required minimum thickness using the maximum distortion energy theory is t = 20 mm

7 0

3 years ago