Identify the kind of simple machine represented by each of these examples: a. A drill bit b. A skateboard ramp c. A boat oar
1 answer:
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Answer:
Turn the heater on
Explanation:
There are two main forces involved in a balloon flight
The downward force is the total weight of the balloon: the air it contains, the gas bag, the basket, the passengers, etc.
The upward force is the weight of the of the air the balloon displaces.
During level flight ,
buoyant force = weight of displaced air - total weight of balloon
If you increase the temperature of the air in the bag, the air molecules spread out and leave through the bottom of the bag.
The balloon still has the same volume, so the weight of displaced outside air stays the same.
However, the balloon has lost some hot inside air, so its total weight decreases.
The upward force is greater than the downward force, so the balloon rises.
The area of the circle with radius r is
A = πr²
The rate of change of area with respect to time is
The rate of change of the radius is given as
Therefore
When r = 10 ft, obtain
Answer: - 40π ft²/s (or - 127.5 ft²/s)
A = πr²
The rate of change of area with respect to time is
The rate of change of the radius is given as
Therefore
When r = 10 ft, obtain
Answer: - 40π ft²/s (or - 127.5 ft²/s)