Ask question

Ask question

All categories

2 years ago

15

When aluminum foil is formed into a loose ball, it can float on water. But when the ball of foil is pounded flat with a hammer,

the foil sinks. why?

1 answer:

docker41 [41]2 years ago

8 0

Air caught in the ball of foil makes the ball less dense than water

You might be interested in

A car starts from a stopped position at a red light. At the end of 30 seconds, its speed is 20 meters per second. What is the ac

Gnoma [55]

A=deltav/t
Vf=20m/s
Vi=0m/s
(20-0)/30
=0.667 m/s^2

5 0

2 years ago

Niobium metal becomes a superconductor when cooled below 9K. Itssuperconductivity is destroyed when the surface magnetic fieldex

elena-14-01-66 [18.8K]

Answer:

the maximum current is 500 A

Explanation:

Given the data in the question;

the B field magnitude on the surface of the wire is;

B = μ₀i / 2πr

we are to determine the maximum current so we rearrange to find i

B2πr = μ₀i

i = B2πr / μ₀

given that;

diameter d = 2 mm = 0.002 m

radius = 0.002 / 2 = 0.001 m

B = 0.100 T

we know that permeability; μ₀ = 4π × 10⁻⁷ Tm/A

so we substitute

i = (0.100)(2π×0.001 ) / 4π × 10⁻⁷

i = 500 A

Therefore, the maximum current is 500 A

4 0

2 years ago

(a) What resonant frequency would you expect from blowing across the top of an empty soda bottle that is 18 cm deep, if you assu

V125BC [204]

Answer:

476.387 Hz

714.583 Hz

Explanation:

L = Length of tube

v = Speed of sound in air = 343 m/s

Frequency for a closed tube is given by

$f=\dfrac{v}{4L}\\\Rightarrow f=\dfrac{343}{4\times 0.18}\\\Rightarrow f=476.389\ Hz$

The frequency is 476.387 Hz

If it was one third full $L=0.18-\dfrac{1}{3}0.18$

$f=\dfrac{v}{4L}\\\Rightarrow f=\dfrac{343}{4\times (0.18-\dfrac{1}{3}0.18)}\\\Rightarrow f=714.583\ Hz$

The frequency is 714.583 Hz

5 0

2 years ago

What is the best explanation for the observation that the electric charge on the stem became positive as the charged bee approac

topjm [15]

Answer:

Option B seems to be the appropriate choice,

Explanation:

The given question is incomplete. Please find the attachment of the complete question.

From either the principle or law of the Coulombs, there would have been either pressure (force) through attachment or repulsion amongst charges.
It is evident from the analysis presented that perhaps the bee becomes positively (+) charged and would have been drawn either by negatively (-) charged roots of the plants or stem.

As a consequence, the vegetation is electric current polarized because as activated bee pursued.

3 0

2 years ago

True or False. Only the initial ball carrier<br><br> can recover a fumble.

Mrrafil [7]

Answer:

A fumbled ball may be recovered and advanced by either team

hope it helps

4 0

2 years ago

Read 2 more answers