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guapka [62]
3 years ago
11

What real-world examples show no work being done? Can you think of examples other than resisting the force of gravity?

Physics
1 answer:
GalinKa [24]3 years ago
8 0

-- pushing on a brick wall

-- standing on your little brother's back so that he can't get up

-- taking a nap while on the job

-- squeezing anything that doesn't yield to your squeeze, such as a glass bottle or your girl friend

-- watching TV

-- solving math problems in your head

-- making pictures out of clouds in the sky

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What is Newton's Second Law of Motion?
Stolb23 [73]

Answer:

C.

Explanation:

If u really need it, just comment.

7 0
3 years ago
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When the force on an object and the object’s displacement are in different directions, which component of the force does work?
podryga [215]

Answer:

It should be b hope it helps :)

Explanation:

8 0
3 years ago
Two students hear the same sound and their eardrums receive the same power from the sound wave. The sound intensity at the eardr
Margaret [11]

Answer:

a. d₁/d₂ = 1.09 b. 0.054 mW

Explanation:

a. What is the ratio of the diameter of the first student's eardrum to that of the second student?

We know since the power is the same for both students, intensity I ∝ I/A where A = surface area of ear drum. If we assume it to be circular, A = πd²/4 where r = radius. So, A ∝ d²

So, I ∝ I/d²

I₁/I₂ = d₂²/d₁² where I₁ = intensity at eardrum of first student, d₁ = diameter of first student's eardrum, I₂ = intensity at eardrum of second student, d₂ = diameter of second student's eardrum.

Given that I₂ = 1.18I₁

I₂/I₁ = 1.18

Since I₁/I₂ = d₂²/d₁²

√(I₁/I₂) = d₂/d₁

d₁/d₂ = √(I₂/I₁)

d₁/d₂ = √1.18

d₁/d₂ = 1.09

So, the ratio of the diameter of the first student's eardrum to that of the second student is 1.09

b. If the diameter of the second student's eardrum is 1.01 cm. how much acoustic power, in microwatts, is striking each of his (and the other student's) eardrums?

We know intensity, I = P/A where P = acoustic power and A = area = πd²/4

Now, P = IA

= I₂A₂

= I₂πd₂²/4

= 1.18I₁πd₂²/4

Given that I₁ = 0.58 W/m² and d₂ = 1.01 cm = 1.01 × 10⁻² m

So, P = 1.18I₁πd₂²/4

= 1.18 × 0.58 W/m² × π × (1.01 × 10⁻² m)²/4

= 0.691244π × 10⁻⁴ W/4 =

2.172 × 10⁻⁴ W/4

= 0.543 × 10⁻⁴ W

= 0.0543 × 10⁻³ W

= 0.0543 mW

≅ 0.054 mW

3 0
3 years ago
When the valve between the 2.00-L bulb, in which the gas pressure is 2.00 atm, and the 3.00-L bulb, in which the gas pressure is
padilas [110]

Answer:

P_{C} = 3.2\, atm

Explanation:

Let assume that gases inside bulbs behave as an ideal gas and have the same temperature. Then, conditions of gases before and after valve opened are now modelled:

Bulb A (2 L, 2 atm) - Before opening:

P_{A} \cdot V_{A} = n_{A} \cdot R_{u} \cdot T

Bulb B (3 L, 4 atm) - Before opening:

P_{B} \cdot V_{B} = n_{B} \cdot R_{u} \cdot T

Bulbs A & B (5 L) - After opening:

P_{C} \cdot (V_{A} + V_{B}) = (n_{A} + n_{B})\cdot R_{u} \cdot T

After some algebraic manipulation, a formula for final pressure is derived:

P_{C} = \frac{P_{A}\cdot V_{A} + P_{B}\cdot V_{B}}{V_{A}+V_{B}}

And final pressure is obtained:

P_{C} = \frac{(2\,atm)\cdot (2\,L)+(4\,atm)\cdot(3\,L)}{5\,L}

P_{C} = 3.2\, atm

5 0
3 years ago
Use the diagram below modeling a football kicked from a horizontal surface B
djyliett [7]
B is the correct one
5 0
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