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3 years ago

A ball is kicked from the top of a building with a velocity of 50 m/s and lands 165 m away from the base of the building.

Physics

1 answer:

Akimi4 [234]3 years ago

3 0

Answer:

3.1 s

Explanation:

we can assume that this motion has a horizontal projectile motion.

projectile motion happens when an object is subjected to only gravity. Gravity acts to influence the vertical motion of the projectile, it makes a vertical acceleration.

The horizontal motion of the projectile is the result of the constant velocity of the object.We assume no acceleration in the horizontal direction.

applying motion equations

where

s - distance

u - initial velocity

a-acceleration

t - time

s = ut + (1/2)at²

→ 165 = 50t + 0 (as no acceleration is in horizontal direction)

t = 3.1 s

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A. a bicycle chain is an example of a compound machine

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3 years ago

A heat pump is to be used for heating a house in winter. The house is to be maintained at 70°F at all times. When the temperatur

Anna35 [415]

Answer:

$\dot{W_{H} } = 4244.48 Btu/h$

Explanation:

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Heat is extracted at 40°F i.e $T_{L} = 40^{0}F = 40 + 460 = 500 R$

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$COP = \frac{T_{H} }{T_{H} - T_{L} } \\COP = \frac{530 }{530 - 500 }\\ COP = \frac{530}{30} \\COP = 17.67$

The minimum power required to run the heat pump is given by the formula:

$\dot{W_{H} } = \frac{\dot{Q_{H} }}{COP} \\$ ...............(*)

Where the heat losses from the house, $\dot{Q_{H} } = 75,000 Btu/h$

Substituting these values into * above

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3 years ago

The membrane of a living cell can be approximated by a parallel-plate capacitor with plates of area 4.50×10−9 m2 , a plate separ

Marizza181 [45]

The energy stored in the membrane is $6.44\cdot 10^{-14} J$

Explanation:

The capacitance of a parallel-plate capacitor is given by

$C=\frac{k\epsilon_0 A}{d}$

where

k is the dielectric constant of the material

$\epsilon_0$ is the vacuum permittivity

A is the area of the plates

d is the separation between the plates

For the membrane in this problem, we have

k = 4.6

$A=4.50\cdot 10^{-9} m^2$

$d=8.1\cdot 10^{-9} m$

Substituting, we find its capacitance:

$C=\frac{(4.6)(8.85\cdot 10^{-12})(4.50\cdot 10^{-9})}{8.1\cdot 10^{-9}}=2.26\cdot 10^{-11} F$

Now we can find the energy stored: for a capacitor, it is given by

$U=\frac{1}{2}CV^2$

where

$C=2.26\cdot 10^{-11} F$ is the capacitance

$V=7.55\cdot 10^{-2} V$ is the potential difference

Substituting,

$U=\frac{1}{2}(2.26\cdot 10^{-11} F)(7.55\cdot 10^{-2})^2=6.44\cdot 10^{-14} J$

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3 years ago

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Ulleksa [173]

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3 years ago

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Viefleur [7K]

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s this is the time to fall from the top; it would take the same time to travel

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3 years ago

Read 2 more answers