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3 years ago

7

Explain why a balloon filled with air cannot float in the middle of a room without moving downwards but a helium balloon of the

same size can?

1 answer:

ELEN [110]3 years ago

6 0

Helium is less dense than normal air

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To warm 2.0 l of tea (d = 1.01 g/ml; sp. heat = a cook places a 500 g block of stone at a temperature of 200f into the teapot. a

IRISSAK [1]

Volume of tea V = 2.0L = 2000 mL density d = 1.01 g/ mL mass of tea m = V * d = 2000mL * 1.01g/mL = 2020 gWhen we assume that the tea was initially at 72, the final temperature of the tea in F is 91.
The answer in this question is B. 91

4 0

3 years ago

How does solar energy produce electricity?

elena-14-01-66 [18.8K]

By the use of "Solar cells" or "Solar panel", we can trap solar energy in silicon/germanium rods, then we can convert in into electricity too.

Hope this helps!

8 0

2 years ago

There is a small scratch on a disco record located 14.5 cm from the center. When played, the scratch makes the record skip 30 ti

LuckyWell [14K]

Answer:

The linear speed of scratch is 45.55 cm/dec

Explanation:

The scratch located from the center at radial distance = 14.5 cm.

Each minute the skip of scratch when disco record played = 30 times

Since, the scratch on the disc start revolving when disc is played and in one minute the scratch revolve 30 times. Therefore, the revolution = 30 RPM

Below is the calculation of linear speed of the scratch.

$Angular \ velocity, \ w \ = \frac{2 \pi \times RPM}{60} \\$

$w = \frac{2 \pi \times 30}{60} = \pi \ rad/dec \\$

$Linear \ velocity = wr \\$

$r = radial \ distance \\$

$v = \pi \times 14.5 \\$

$v = 45.55 cm/dec$

3 0

2 years ago

4. A helicopter is flying at a height of 1.5km. If it has 50MJ of G.P.E., what is the mass of the

lapo4ka [179]

Its its tony lopez

explanation

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3 years ago

Gina was summarizing what she read to her friends and shared this image, calling it a digital signal. Is she correct in saying t

fredd [130]

The image shows a continuous signal and is not made of numbers, so this signal is an analog signal. Gina is not correct in her identification of the signal.

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3 years ago

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