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3 years ago

I DONT NEED ANYONE TO ANSWER QUESTION BUT IS THERE ANYONE THAT CAN HELP ME ON QUIZZES FOR FREE

Physics

2 answers:

olchik [2.2K]3 years ago

8 0

Answer:

Sorry

Explanation:

lol i need someone for myself to do that

pochemuha3 years ago

7 0

Answer:

Not me

Explanation:

Sorry

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Which of these statements best explains why trees in a forest do not grow very close to one another?

SpyIntel [72]

Answer: trees compete for resources directly around them .

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3 years ago

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What happens when a wave encounters a boundary and then goes back to the original medium?

lawyer [7]

It causes a movement of convection in the water resulting in a pulling current.

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3 years ago

A hollow plastic sphere is held below the surface of a fresh-water lake by a cord anchored to the bottom of the lake. The sphere

Naya [18.7K]

Answer: a) B = 6811N

b) m = 603.2kg

c) 86.8%

Explanation: <em>Buoyant force</em> is a force a fluid exerts on a submerged object.

It can be calculated as:

$B=\rho_{fluid}.V_{obj}.g$

where:

$\rho_{fluid}$ is density of the fluid the object is in;

$V_{obj}$ is volume of the object;

g is acceleration due to gravity, is constant and equals 9.8m/s²

a) For the hollow plastic sphere, density of water is 1000kg/m³:

$B=10^{3}.0.695.9.8$

B = 6811N

b) Anchored to the bottom, the forces acting on the sphere are <u>Buoyant</u>, <u>Tension</u> and <u>Force due to gravity</u>:

B = T + $F_{g}$

B = T + mg

mg = B - T

$m=\frac{B - T}{g}$

Calculating:

$m=\frac{6811 - 900}{9.8}$

m = 603.2kg

c) When the shpere comes to rest on the surface of the water, there are only <u>buoyant</u> <u>and</u> <u>gravity</u> acting on it:

B = m.g

$\rho_{w}.V_{sub}.g=m.g$

$V_{sub}=\frac{m}{\rho_{w}}$

$V_{sub}=\frac{603.2}{1000}$

$V_{sub}$ = 0.6032m³

Fraction of the submerged volume is:

$\frac{V_{sub}}{V_{obj}}$ = $\frac{0.6932}{0.695}$ = 0.868

<u />

3 0

3 years ago

An especially violent lightning bolt has an average current of 1.89 x 103 A lasting 0.133 s. How much charge is delivered to the

Rasek [7]

<h2> Charge = 25.9 $Ampsec^{-1}$ </h2>

Explanation:

Given,

The average current (I) = ${1.89} \times {103 A}$ and

Time period (T) = 0.133 s

The charge is calculated by multiplying the current to the time period.

Hence,

To find, the charge delivered to the ground by the lightning bolt(Q) = ?

By applying the formula of charge that is-

Charge(Q) = $Current(I) \times Time(T)$

∴ Charge(Q) = ${1.89} \times {103 A}$ $\times 0.133 s$

= 25.89111 $As^{-1}$

= 25.9 $As^{-}$

<h3>Thus, the charge of 25.9 $Ampsec^{-1}$ is delivered to the ground by the lightning bolt.</h3>

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4 years ago

A balloon of mass M is floating motionless in the air. A person ofmass less than M is on a rope ladder hanging from the balloon.

andreyandreev [35.5K]

Answer:

Correct answer letter C.

Explanation:

As we see in this problem, the total linear momentum is conserved, since there are no external forces acting in that system.

So, we can say that $\Delta p = 0$ or $p_{initial} = p_{final}$

Now, the initial momentum is zero, because before the person starts climbing, the system (balloon plus person) are floating motionless, therefore we have:

$0=m_{person}v_{person}+M_{balloon}V_{balloon}$

$V_{balloon}=-\frac{m_{person}}{M_{balloon}}v_{person}$ (1)

We know that M > m, therefore, m/M < 1 and using (1) we can deduce that V(balloon) < v(person).

Finally, we can say that the balloon moves down (because of the minus sign of V(balloon)) and its speed is less than v(person). Correct answer letter C.

I hope it helps you!

3 0

3 years ago