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3 years ago

We cannot consider something to be work unless

Physics

2 answers:

bogdanovich [222]3 years ago

8 0

Answer:

When displacement caused by force is zero or force is perpendicular to displacement then we consider there will be no work done

Explanation:

We know that work done is given by $W=Fdcos\Theta$ , here F is force applied and d is the displacement caused by the force

Now there are two case in which work done will be zero that is, either displacement is zero or $\Theta =90^{\circ}$ that is force and displacement are perpendicular to each other

So when displacement caused by force is zero or force is perpendicular to displacement then we consider there will be no work done

Alla [95]3 years ago

4 0

We cannot consider something to be work unless <span>force applied causes movement of an object in the same direction as the applied force. </span>

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A space explorer is moving through space far from any planet or star. He notices a large rock, taken as a specimen from an alien

yaroslaw [1]

He should push it gently.
This is because the forces of resistance this situation are minimal, so the rock will not slow as it would on Earth. Kicking the rock may result in it travelling too fast and hitting something else, causing damage. Moreover, the rock could start rebounding off of surfaces and create havoc.

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3 years ago

Which units are used to express sound intensity?

grigory [225]

Answer: decibels

Explanation:

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3 years ago

An oceanographer is studying how the ion concentration in seawater depends on depth. She makes a measurement by lowering into th

Black_prince [1.1K]

Answer:

a) R = ρ₀ L /π(r_b² - R_a²) , b) ρ₀ = V / I π (r_b² - R_a²) / L

Explanation:

a) The resistance of a material is given by

R = ρ l / A

where ρ is the resistivity, l is the length and A is the area

the length is l = L and the resistivity is ρ = ρ₀

the area is the area of the cylindrical shell

A = π r_b² - π r_a²

A = π (r_b² - r_a²)

we substitute

R = ρ₀ L /π(r_b² - R_a²)

b) The potential difference is related to current and resistance by ohm's law

V = i R

we subsist the expression of resistance

V = I ρ₀ L /π (r_b² - R_a²)

ρ₀ = V / I π (r_b² - R_a²) / L

6 0

3 years ago

Two friends of different masses are on the playground. They are playing on the seesaw and are able to balance it even though the

Westkost [7]

Answer:

They are able to balance torques due to gravity.

$F_1 L_1 = F_2L_2$

Explanation:

When two friends of different masses will balance themselves on see saw then at equilibrium position the see saw will remain horizontal

This condition will be torque equilibrium position where the see saw will not rotate

Here we can say

$F_1 L_1 = F_2L_2$

here we know that force is due to weight of two friends

and their positions are different with respect to the lever about which see saw is rotating

since both friends are of different weight so they will balance themselves are different positions as per above equation

5 0

3 years ago

Two wires each carry 10.0 A of current (in opposite directions) and are 2.50 mm apart. What is the magnetic field 37.0 cm away a

lyudmila [28]

Answer:

see answer below

Explanation:

Before we do any kind of calculation, we need to convert the proper units of the exercise. All the units of distance must be in meters, so, let's change distance of the wire, and the magnetic field to meters:

Separation between the wires are 2.5 mm:

2.5 mm * (1 m / 1000 mm) = 0.0025 m

The distance of P from the bottom of the wires is 37 cm:

37 cm * (1 m/100 cm) = 0.37 m

The distance of P from the top of the wires is just the sum of the two distances:

R = 0.37 + 0.0025 = 0.3725 m

Now that we have the distance, we can determine the magnetic field, using the following expression:

B = B(bottom) - B(top) or just B₂ - B₁

And B = μ₀ I / 2πR

Replacing in the above expression we have:

B = μ₀ I / 2π ( 1/R₂ - 1/R₁)

Now we can determine the magnetic field:

B = (4πx10⁻⁷ * 10 / 2π) (1/0.37 - 1/0.3725)

Which means that the magnetic field is out of the page.

Hope this helps

4 0

3 years ago