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3 years ago

Explain why objects moving in fluids must have special shapes ?

Physics

1 answer:

Alexus [3.1K]3 years ago

8 0

Explanation:

Fluids exert both drag and lift forces on moving objects. Drag is the frictional force opposing motion. Lift is the force perpendicular to motion.

Some objects, like parachutes, are designed with large cross sectional areas to increase drag force. Usually though, objects are designed to minimize drag force. It's why cars, planes, and boats have sleek shapes.

Airplane wings have shapes called airfoils that generate lift. It's what makes them fly. The same shape is found in racecar spoilers. These spoilers use lift force to push down on the rear tires, increasing traction.

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You are trying to determine the specific gravity of a solid object that floats in water. If m is the mass of your object, mS is

Alisiya [41]

Answer:

Specific Gravity = m/[m(s)-m(os)]

Explanation:

Specific gravity, also called relative density, is the ratio of the density of a substance to the density of a reference substance. By this definition we need to find out the ratio of density of the object of mass m to the density of the surrounding liquid.

m = mass of the object

Weight in air

W (air) = mg, where g is the gravitational acceleration

Weight with submerged with only one mass

m(s)g + Fb = mg + m(b)g, consider this to be equation 1

where Fb is the buoyancy force

Weight with submerged with both masses

m(os)g + Fb’ = mg + m(b)g, consider this to be equation 2

equation 1 – equation 2 would give us

m(s)g – m(os)g = Fb’ – Fb

where Fb = D x V x g, where D is the density of the liquid the object is submerged in, g is the force of gravity and V is the submerged volume of the object

m(s)g – m(os)g = D(l) x V x g

m(s) – m(os) = D(l) x V

we know that Mass = Density x V, which in our case would be, D(b) x V, which also means

V = Mass/D(b), where D(b) is the density of the mass

Substituting V into the above equation we get

m(s) – m(os) = [D(l) x m)/ D(b)]

Rearranging to get the ratio of density of object to the density of liquid

D(b)/D(l) = m/[m(s)-m(os)], where D(b)/D(l) denotes the specific gravity

8 0

3 years ago

A group of scientists have obtained some experimental results.

topjm [15]

In order best to find out whether the obtained experimental results are worth mor etime and resources the group of scientists should present their results (could be done also in poster session) to other scientists in order to hear their opinion and get a feedback. The shoudl also ask another researchers to redo the experiments and to compare the results.

4 0

3 years ago

Read 2 more answers

A car accelerates from rest at a constant rate of 2m/s2 for 5s. what is the speed of a car at the end of that time?

Fiesta28 [93]

Good afternoon.

We have:

$\mathsf{V_0 = 0}\\ \mathsf{a = 2 \ m/s^2}\\ \mathsf{t = 5 \ s}$

The function of velocity:

$\mathsf{V = V_0+at}\\ \\ \mathsf{V = 0 + 2t}\\ \\ \mathsf{V = 2t}$

For t = 5 s:

$\mathsf{V = 2\cdot 5}\\ \\ \boxed{\mathsf{V = 10 \ m/s}}$

4 0

3 years ago

Three plant like organisms which cannot produce their own food are

SpyIntel [72]

I can only offer you one which is mushroom. They're fungus' and they can't produce their own food. They get their food from decaying and dead animals and absorb it through their roots.

8 0

3 years ago

A car traveling at a speed of 30.0 m/s encounters an emergency and comes to a complete stop. how much time will it take for the

Vedmedyk [2.9K]

Answer:7.5seconds

Explanation:

V=0 u=30m/s a=-4m/s^2

t=(v-u)/a

t=(0-30)/-4=-30/-4

t=7.5second

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3 years ago