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3 years ago

When there is no number in front of a chemical formula in a chemical equation, what number is understood?

1 answer:

5 0

<span>The number in front is the number of molecules (or atoms) taking part in the (balanced) chemical reaction equation.</span>

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A wheel of mass 4kg is pulled up a plane inclined at 30° to the horizontal by a force of 45N applied to the axle and parallel to

Len [333]

Answer:

v = 10 m/s

Explanation:

Let's assume the wheel does not slip as it accelerates.

Energy theory is more straightforward than kinematics in my opinion.

Work done on the wheel

W = Fd = 45(12) = 540 J

Some is converted to potential energy

PE = mgh = 4(9.8)12sin30 = 235.2 J

As there is no friction mentioned, the remainder is kinetic energy

KE = 540 - 235.2 = 304.8 J

KE = ½mv² + ½Iω²

ω = v/R

KE = ½mv² + ½I(v/R)² = ½(m + I/R²)v²

v = √(2KE / (m + I/R²))

v = √(2(304.8) / (4 + 0.5/0.5²)) = √101.6

v = 10.07968...

5 0

3 years ago

A projectile is shot at an angle 45 degrees to the horizontalnear the surface of the earth but in the absence of air resistance.

juin [17]

Answer:

Explanation:

Given

For first case

launch angle $\theta =45^{\circ}C$

at highest point $h=150 m/s$

$150=u\cos 45$

$u=\frac{150}{\cos 45}=212.132 m/s$

For second case

$\theta _2=37^{\circ}C$

at highest Point velocity is $u\cos \theta _2$

$=212.132\times \cos 37$

$=169.41 m/s$

as there is no acceleration in x direction therefore horizontal velocity is same

7 0

3 years ago

Read 2 more answers

A package of aluminum foil contains 50. Ft2 of foil, which weighs approximately 7.0 oz . Aluminum has a density of 2.70 g/cm3. W

kumpel [21]

We know density = Mass / Volume

So Volume = Mass/Density

Volume = Area * Thickness

$Area = 50 ft^2 = 4.645152 m^2\\ \\Mass = 7 oz = 0.198447 kg\\ \\Density = 2.70 g/cm^3 = 2700 kg/m^3\\ \\Substituting \\ \\4.645152 *t = \frac{0.198447}{2700} \\ \\t = 1.58*10^{-5}m = 1.58*10^{-2}mm$

So the approximate thickness of the foil in millimeters = $1.58*10^{-2}mm$

6 0

3 years ago

Describe what happens to pressure as the force exerted on a given area increases.

Goryan [66]

That's the definition of pressure ... force on a given area.

So when that force increases, it's an increase in pressure.

4 0

3 years ago

mina [271]

Answer:

B West

Explanation:

5 0

3 years ago