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wlad13 [49]
2 years ago
9

You throw a ball straight up. Compare the sign of the work done by gravity while the ball goes up with the sign of the work done

by gravity while it goes down.
a. Work is + on the way up and + on the way down
b. Work is + on the way up and - on the way down
c. Work is - on the way up and + on the way down
d. Work is - on the way up and - on the way down
Physics
1 answer:
Elden [556K]2 years ago
8 0

Answer:

c. Work is - on the way up and + on the way down

Explanation:

Work done is given as the product of the applied force and the displacement of the object.

Work done = F x d

Work done = mg x d

where;

g is acceleration due to gravity = 9.8 m/s²

When the ball goes up, it moves against the force of gravity which tends to pull every object downwards. Since the ball moves against gravity, the work done is negative.

Also, when the ball goes down, it moves in the direction of gravity which acts downwards. Since the ball moves in the same direction as gravity, the work done is positive.

The correct option is "C. Work is negative (-) on the way up and positive (+) on the way down"

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iron β is a solid phase of iron still unknown to science. The only difference between it and ordinary iron is that Iron β forms
saw5 [17]

Answer:

8.60 g/cm³

Explanation:

In the lattice structure of iron, there are two atoms per unit cell. So:

\frac{2}{a^{3} }  = \frac{N_{A} }{V_{molar} } where V_{molar}  = \frac{A}{\rho } an and A is the atomic mass of iron.

Therefore:

\frac{2}{a^{3} } = \frac{N_{A} * p }{A}

This implies that:

A = (\frac{2A}{N_{A} * p)^{\frac{1}{3} }  }

  = \frac{4}{\sqrt{3} }r

Assuming that there is no phase change gives:

\rho = \frac{4A}{N_{A}(2\sqrt{2r})^{3}   }

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3 years ago
Vector e is 0.111m long in a 90 deg direction. Vector f is 0.233 m long in 400 deg direction. Find the direction of their vector
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Answer:

50.6

Explanation:

7 0
3 years ago
A tree loses water to the air by the process of transpiration at the rate of 110 g/h. This water is replaced by the upward flow
Ksivusya [100]

Answer:

The answer is 1.87nm/s.

Explanation:

The 110g/hr  water loss must be replaced by 110g/hr of sap. 110g of sap corresponds to a volume of  

110g \div \dfrac{1040*10^3g}{1*10^6cm^3}  = 106cm^3

thus rate of sap replacement is

106cm^3/hr = 106*10^{-6}m^3/3600s  = 2.94*10^{-8}m^3/s

The volume of sap in the vessel of length x is

V = Ax,

where A is the cross sectional area of the vessel.

For 2000 such vessels, the volume is

V = 2000Ax

taking the derivative of both sides we get:

\dfrac{dV}{dt} = 2000A \dfrac{dx}{dt}

on the left-hand-side \dfrac{dx}{dt} is the velocity v of the sap, and on right-hand-side \dfrac{dV}{dt}  = 2.94*10^{-8}m^3/s; therefore,

2.94*10^{-8}m^3/s=2000Av

and since the cross-sectional area is

A = \pi (\dfrac{100*10^{-3}m}{2} )^2 = 7.85*10^{-3}m^2;

therefore,

2.94*10^{-8}m^3/s =2000(7.85*10^{-3}m^2)v

solving for v we get:

v = \dfrac{2.94*10^{-8}m^3/s}{2000(7.85*10^{-3}m^2)}

\boxed{v =1.875*10^{-9}m/s = 1.875nm/s}

which is the upward speed of the sap in each vessel.

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3 years ago
What area of the earth contains semi-solid rock and lava
katrin2010 [14]

Answer:

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2 years ago
<img src="https://tex.z-dn.net/?f=what%20%5C%3A%20is%20%5C%3A%20refraction%20%5C%3A%20of%20%5C%3A%20light%20%5C%3A%20%20%7B%3F%7
topjm [15]

When light passes through one transparent medium to another transperent medium it bends and that beding of light is know as refraction of light !

8 0
3 years ago
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