<u>Answer</u>
1. <span>c. convection
</span>2. b. When it is very cold
<u>Explanation</u>
Water like any other liquid transfer heat energy through convection.
When a pot of water is put on a stove, the water at the top gets hot primarily by <span>convection.
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A supperconductor is a material that can conduct electric current with no resistance at all.
The supperconductivity can be achieved under cooled temperatures.
Certain materials can become superconductors under what conditions? <u>When it is very cold</u>
Explanation:
It is given that,
Mass of the bullet, m₁ = 0.093 kg
Initial speed of bullet, u₁ = 100 m/s
Mass of block, m₂ = 2.5 kg
Initial speed of block, u₂ = 0
We need to find the speed of the block after the bullet embeds itself in the block. Let it is given by V. On applying the conservation of linear momentum as :
V = 3.58 m/s
So, the speed of the bullet is 3.58 m/s. Hence, this is the required solution.
Sure ! Here's one way to look at it that nobody ever tells you:
Remember:
-- A fraction with the same thing on the top and bottom is equal to ' 1 '.
-- You can multiply a quantity by ' 1 ' all day long without changing its value.
In order to convert units, you multiply the original quantity by one or more fractions. Each fraction has the same thing on top and bottom, but in different units, so it's equal to ' 1 '. Then you go through the expression that you've built, and 'cancel' things ... dividing a unit out where it appears on both the top and bottom.
Example:
How many seconds are there in 1 day ?
(Convert one day to units of seconds.)
(1 day) x (24 hr/day) x (60min/hr) x (60 sec/min)
That's 1 day, multiplied by 3 fractions. Each fraction is equal to ' 1 ' because it has the same thing on top and bottom, only in different units.
Now, look at the first 2 terms. They have 'day' on top and 'day' on the bottom, so 'day' can be 'canceled' (actually divided) out of the top and bottom.
Similarly, the 2nd and 3rd terms have 'hour' on top and bottom, so 'hour' can be canceled and disappear from the whole expression. The 3rd and 4th terms have 'minute' on the top and bottom, so 'minute' can be canceled.
Finally, the only unit that's still there and hasn't been cancelled is 'second'. The whole expression now says
(1) x (24) x (60) x (60 seconds) = 86,400 seconds
and <em>there's</em> the conversion of units from 'day' to 'second'.
The whole trick is to pick the right fractions, and to decide whether to write each fraction either right-side-up or upside-down. The idea is to decide which unit you want to get rid of, and then arrange things so that it's on top once and on the bottom once, so that you can cancel it and make it disappear.
And that's what I can give you on the topic of converting units. To me, it's always been very helpful.
The force that one massive object exerts to attract another object is called gravity or gravitational pull.