
Since the diameter of helium atom is approximately
, therefore the diameter of helium atom in nano meter,

Answer: D
1200
Explanation:
Song 1 is spotted with a cube sign.
At 3 minute, trace the spot to the vertical axis. And you will notice that it a little bit above 10.
Since it is above 10, let assume it is equal to 12.
The number of song downloaded are in hundreds. Therefore, multiply the 12 by 100
12 × 100 = 1200 downloads
Approximately, song 1 has 1200 downloads at minute 3
If your speed changes from 10 km/h to 6 km/h then
you have an acceleration.
Whether it's a positive or negative one completely depends
on which direction you decided to call the positive direction,
when you started considering your speed and its changes.
If you decided to call the direction in which you're traveling
the positive direction, then a decrease in your speed is a
negative acceleration.
But you could just as easily have said that you're traveling
in the negative direction. If you did that, then a decrease in
your speed would be a positive acceleration.
It's completely up to you, and how you define things.