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3 years ago

What could you do to find the density of a fork, knife, and a spoon?

Physics

2 answers:

Effectus [21]3 years ago

6 0

Answer:

Use the formula D=m/v

Explanation: In order to find the volume for these objects, use a ruler and measure the length, width, and height. Proceed to multiply them all together, L*W*H. To find the mass of an object, I would say to use a triple beam balance. After finding both the mass and volume of you object, use the formula D = m/v and you'll get your answer.

serg [7]3 years ago

4 0

Answer:

Density is equal to mass divided by volume.

Explanation:

Density = mass / volume

p=m/v

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If 2.0 mol of gas a is mixed with 1.0 mol of gas b to give a total pressure of 1.6 atm, what is the partial pressure of gas a an

devlian [24]

PA = 1.06 atm and PB = 0.53 atm

8 0

3 years ago

Read 2 more answers

Consider a heat engine that inputs 10 kJ of heat and outputs 5 kJ of work. What are the signs on the total heat transfer and tot

Oksi-84 [34.3K]

Answer:

Total heat transfer is positive

Total work transfer is positive

Explanation:

The first law of thermodynamics states that when a system interacts with its surrounding, the amount of energy gained by the system must be equal to the amount of energy lost by the surrounding. In a closed system, exchange of energy with the surrounding can be done through heat and work transfer.

Heat transfer to a system is positive and that transferred from the system is negative.

Also, work done by a system is positive while the work done on the system is negative.

Therefore, from the question, since the heat engine inputs 10kJ of heat, then heat is being transferred to the system. Hence, the sign of the total heat transfer is positive (+ve)

Also, since the heat engine outputs 5kJ of work, it implies that work is being done by the system. Hence the sign of the total work transfer is also positive (+ve).

5 0

3 years ago

a man can row a boat at 4 km per hour in still water. he rolls the boat two kilometre upstream and 2 kilometre back to a startin

stiv31 [10]

Answer:

I would say since it is still water the stream flow is 0km/h. Especially because he needs the same time upstream as He does down stream.

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3 years ago

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A high-jumper, having just cleared the bar, lands on an air mattress and comes to rest. Had she landed directly on the hard grou

Hoochie [10]

Answer:

e. the air mattress exerts the same impulse, but a smaller net avg force, on the high-jumper than hard-ground.

Explanation:

This is according to the Newton's second law and energy conservation that the force exerted by the hard-ground is more than the force exerted by the mattress.

The hard ground stops the moving mass by its sudden reaction in the opposite direction of impact force whereas the mattress takes a longer time to stop the motion of same mass in a longer time leading to lesser average reaction force.

Mathematical expression for the Newton's second law of motion is given as:

$F=\frac{dp}{dt}$ ............................................(1)

where:

dp = change in momentum

dt = time taken to change the momentum

We know, momentum:

$p=m.v$

Now, equation (1) becomes:

$F=\frac{d(m.v)}{dt}$

∵mass is constant at speeds v << c (speed of light)

$\therefore F=m.\frac{dv}{dt}$

and, $\frac{dv}{dt} =a$

where: a = acceleration

$\Rightarrow F=m.a$

also

$F\propto \frac{1}{dt}$

so, more the time, lesser the force.

& Impulse:

$I=F.dt$

$I=m.a.dt$

$I=m.\frac{dv}{dt}.dt$

$I=m.dv=dp$

∵Initial velocity and final velocity(=0), of a certain mass is same irrespective of the stopping method.

So, the impulse in both the cases will be same.

4 0

3 years ago

A stereo speaker is placed between two observers who are 35 m apart, along the line connecting them. If one observer records an

kompoz [17]

Answer:

x = 2,864 m , Ra = 32.1 m

Explanation:

Let's solve this problem in parts, let's start by finding the intensity of the sound in each observer

observer A β = 64 db

β = 10 log Iₐ / I₀

where I₀ = 1 10⁻¹² W / m²

Iₐ = I₀ 10 (β/ 10)

let's calculate

Iₐ = 1 10⁻¹² (64/10)

Iₐ = 2.51 10⁻⁶ W / m²

Observer B β = 85 db

I_b = 1 10-12 10 (85/10)

I_b = 3.16 10⁻⁴ W / m²

now we use that the emitted power that is constant is the intensity over the area of the sphere where the sound is distributed

P = I A

therefore for the two observers

P = Ia Aa = Ib Ab

the area of a sphere is

A = 4π R²

we substitute

Ia 4pi Ra2 = Ib 4pi Rb2

Ia Ra2 = Ib Rb2

Let us call the distance from the observer be to the haughty R = ax, so the distance from the observer A to the haughty is R = 35 ax; we substitute

Ia (35 -x) 2 = Ib x2

we develop and solve

35-x = Ra (Ib / Ia) x

35 = [Ra (Ib / Ia) +1] x

x (11.22 +1) = 35

x = 35 / 12.22

x = 2,864 m

This is the distance of observer B

The distance from observer A

Ra = 35 - x

Ra = 35 - 2,864

Ra = 32.1 m

8 0

3 years ago