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)
The acceleration of gravity on or near the surface of the Earth is 9.8 m/s².
Anything acted on only by gravity loses 9.8 m/s of upward speed, or gains
9.8 m/s of downward speed, every second.
Leaping straight upward at 1.8 m/s, Tina keeps rising until she runs out of
upward speed. That happens in (1.8/9.8) = 0.1837 second after the leap.
After that, Finkel's First Law of Motion takes over:
"What goes up must come down."
The dropping part of the leap is symmetrical with the first. Please don't
make me go through proving it. Tina hits the floor at the same speed of
1.8 m/s with which she left it, and it takes the same amount of time to drop
from the peak to the floor as it took to rise from the floor to the peak.
So her total time out of contact with the floor is
2 x (0.1837 sec) = 0.367 second (rounded)
Answer:
The answer is the number of protons in its atom
Explanation:
The net force needed to lift a full grocery sack uniformly is 32.115 N.
<h3>What is Net force?</h3>
When two or more forces are acting on the system of objects, then the to attain equilibrium, net force must be zero.
Given the weight of sack W = 210N and the acceleration a = 1.5m/s².
The mass of the sack will be
m = Weight / acceleration due to gravity
m = 210 N/9.81 m/s²
m = 21.41 kg
Using Newton's second law, the net force will be
F = mass x acceleration
F= 21.41 x 1.5
F = 32.115 N
Thus, the net force is 32.115 N.
Learn more about net force.
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