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3 years ago

Which weighs more a pound of feathers or a pound of bricks

Physics

1 answer:

Alecsey [184]3 years ago

5 0

Answer: neither

Explanation:

both weight exactly one pound. although the quantity of feathers may outnumber the bricks, they both weigh a pound

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If the units of your answer are kg ∙ m2/s3, which of the following types of quantities could your answer be?

kirza4 [7]

Answer:

D. power

Explanation:

kg represents mass

(m/v)² represents velocity squared

Then kg·m²/s² represents mass·velocity² = kinetic energy or potential energy or work.

kg·m²/s³ will be the rate of doing work, which is power

4 0

3 years ago

Read 2 more answers

You throw a tennis ball straight up (neglect air resistance). It takes 7.0 seconds to go up and then return to your hand. How fa

sattari [20]

Answer:

Velocity of throwing = 34.335 m/s

Explanation:

Time taken by the tennis ball to reach maximum height, t = 0.5 x 7 = 3.5 seconds.

Let the initial velocity be u, we have acceleration due to gravity, a = -9.81 m/s² and final velocity = 0 m/s

Equation of motion result we have v = u + at

Substituting

0 = u - 9.81 x 3.5

u = 34.335 m/s

Velocity of throwing = 34.335 m/s

6 0

3 years ago

The distance between two charges a and b is r, and the force between them is F. What is the force between them if the distancbet

Nadusha1986 [10]

See coulomb's law. Force is inversely proportional to the distance squared. So if you multiply r by 2, the force is multiplied by (½)² = ¼.

a. F/4

7 0

3 years ago

Air, considered an ideal gas, is contained in an insulated piston-cylinder assembly outfitted with a paddle wheel. It is initial

Maru [420]

Our data are,

State 1:

$P_1= 10psi=68.95kPa\\V_1 = 1ft^3=0.02831m^3\\T_1 = 100\°F = 310.93K$

State 2:

$P_2 =5psi=34.474kPa\\V_2 = 3ft^3=0.0899m^3$

We know as well that $3BTU=3.16kJ/K$

To find the mass we apply the ideal gas formula, which is given by

$P_1V_1=mRT_1$

Re-arrange for m,

$m= \frac{P_1V_1}{RT_1}\\m= \frac{68.95*0.02831}{(0.287)310.9}\\m=0.021893kg=0.04806lbm\\$

Because of the pressure, temperature and volume ratio of state 1 and 2, we have to

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

Replacing,

$T_2 = \frac{P_2V_2}{P_1V_1}T_1\\T_2 =\frac{34.474*0.0844}{68.95*0.02831}*310.93\\T_2 = 464.217K=375.5\°F$

For conservative energy we have, (Cv = 0.718)

$W = m C_v = 0.718 \Delta T +dw\\dw = W - mv\Delta T\\dw = 3.16-(0.0218*0.718)(454.127-310.93)\\dw = 0.765kJ=0.72BTU$

3 0

3 years ago

What is the action force of a flying bird?

kirill [66]

It is called the reaction force of a bird flying.

7 0

3 years ago