Answer:
Explanation:
mass of first marble 
Initial velocity of the first marble
considering right side as positive
Mass of second marble
After collision first marble moves to the left with a velocity of 18 cm/s
i.e. 
considering
be the velocity of second marble after collision
The Coefficient of restitution is 1 for an elastic collision

Putting values

So, the velocity of the second marble is 22.5 m/s to the right after the collision
(b)Initial kinetic energy =
Final kinetic energy=

Answer:


Explanation:
The speed of sound in the air increases 0.6 m / s for every 1 ° C increase in temperature. An approximate speed can be calculated using the following empirical formula:

Where:

A more exact equation, usually referred to as adiabatic velocity of sound, is given by the following formula:

Where:

Hence:

Now, the Mach number at which an aircraft is flying can be calculated by:

Where:

Therefore:

Answer:
60-100
Explanation:
A normal resting heart rate for adults ranges from 60 to 100 beats per minute. Generally, a lower heart rate at rest implies more efficient heart function and better cardiovascular fitness.
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Answer:
D. The number of winter coats sold and the temperature outside.
Explanation:
A negative correlation can be described as a relationship existing between two variables such that as one of these variables goes up, the other variable would go down and vice versa.
With this explanation in mind, as the temperature outside increases, less winter coats would be sold because an increase in temperature would mean more heat and hotness. People would be uncomfortable wearing thick clothing.
Answer:
The greater the amount of output for a given unit of input, the higher the overall productivity. Businesses generally aim to improve productivity over time to maintain competitiveness and increase the business's profitability. Individuals are familiar with the idea of productivity in their own lives.