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2 years ago

Why is magnetic force a non contact force?

1 answer:

6 0

Bcoz when you place a magnet close enough the magnet attracts or repals without any other fore we dont touch the magnet so it is non contact

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0.235 moles of a diatomic gas expands doing 205 J of work while the temperature drops 88 K. Find Q.? (Unit=J)

Harman [31]

The heat released by the gas is -225 J

Explanation:

First of all, we have to calculate the change in internal energy of the gas, which for a diatomic gas is given by

$\Delta U = \frac{5}{2}nR\Delta T$

where

n = 0.235 mol is the number of moles

$R=8.314\cdot J/mol K$ is the gas constant

$\Delta T = -88 K$ is the change in temperature

Substituting,

$\Delta U = \frac{5}{2}(0.235)(8.314)(-88)=-430 J$

Now we can us the 1st law of thermodynamics to find the heat absorbed/released by the gas:

$\Delta U = Q -W$

where

$\Delta U = -430 J$ is the change in internal energy

Q is the heat

W = 205 J is the heat done by the gas

Solving for Q,

$Q=\Delta U + W = -430 + 205 =-225 J$

Since the sign is negative, it means the heat has been released by the gas.

Learn more about thermodynamics:

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#LearnwithBrainly

5 0

3 years ago

A force of 1.150×103 N pushes a man on a bicycle forward. Air resistance pushes against him with a force of 795 N. If he starts

nalin [4]

Answer:

He has a speed of 16.60m/s after 35.0 meters.

Explanation:

The final velocity can be determined by means of the equations for a Uniformly Accelerated Rectilinear Motion:

$v_{f}^{2} = v_{i}^{2} + 2ad$

$v_{f} = \sqrt{v_{i}^{2} + 2ad}$ (1)

The acceleration can be found by means of Newton's second law:

$\sum F_{net} = ma$

Where $\sum F_{net}$ is the net force, m is the mass and a is the acceleration.

$Fx + Fy = ma$ (2)

All the forces can be easily represented in a free body diagram, as it is shown below.

Forces in the x axis:

$F_{x} = F - F_{air}$ (3)

Forces in the y axis:

$F_{y} = 0$ (4)

Solving for the forces in the x axis:

$F_{x} = F - F_{air}$

Where $F = 1.150x10^{3} N$ and $F_{air} = 795 N$ :

$F_{x} = 1.150x10^{3} N - 795 N$

$F_{x} = 355 N$

Replacing in equation (2) it is gotten:

$Fx + Fy = ma$

$355 N + 0 N = (90.0 Kg)a$

$355 N = (90.0 Kg)a$

$a = \frac{355 N}{90.0Kg}$

$a = \frac{355 Kg.m/s^{2}}{90.0Kg}$

$a = 3.94 m/s^{2}$

So the acceleration for the cyclist is $3.94 m/s^{2}$ , now that the acceleration is known, equation (1) can be used:

$v_{f} = \sqrt{v_{i}^{2} + 2ad}$

However, since he was originally at rest its initial velocity will be zero ( $v_{i} = 0$ ).

$v_{f} = \sqrt{2ad}$

$v_{f} = \sqrt{2(3.94m/s^{2})(35.0m)}$

$v_{f} = 16.60m/s$

He has a speed of 16.60m/s after 35.0 meters

8 0

3 years ago

Swimmers at the beach are tanning on towels. Which method of heat transfer is responsible for their tan? *

Free_Kalibri [48]

Answer:

ratiation

Explanation:

3 0

2 years ago

Read 2 more answers

What is number 14 please tell me

UNO [17]

<span>a thin fibrous cartilage between the surfaces of some joints, e.g., the knee.</span>

3 0

3 years ago

The sensitivity of a measuring instrument is the value of the smallest quantity that can be read or estimated with it. What is t

nirvana33 [79]

Answer:

The smallest part of a millimeter that can be read with a digital caliper with a four digit display is 0.02mm. Thus, it has to be converted to centimetre. So, divide by 10, we then have 0.02/10= *0.002cm* not mm.

6 0

3 years ago