'Suppose your hand moves upward by 0.50m while you are throwing the ball. The ball leaves your hand with an upward velocity of 2
0.0 m/s. Find the magnitude of the force (assumed constant) that your hand exerts on the ball. Ignore air resistance.' Now my question is not 'What is the magnitude' but rather: why did I get (roughly) the same answer using F=ma when you were supposed to use the total mechanical energy (W+K1+U1=K2+U2). So I'm more confused about how the 2 formulas are 'related', what the force actually represents in both, when to use what and if there is an actual difference.
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Answer:
Explanation:
v = Velocity of the breeze = 4 m/s
w = Width of the valley = 5000 m
h = Height of the valley = 1000 m
Volumetric flow rate is given by
= Mass flow rate of pollutant = 25 g/s =
Concentration is given by
The steady state concentration of pollutants in the valley, is .
(a) The angular acceleration of the wheel is given by
where
and 
are the initial and final angular speed of the wheel, and t the time.
In our problem, the initial angular speed is zero (the wheel starts from rest), so the angular acceleration is
(b) The wheel is moving by uniformly rotational accelerated motion, so the angle it covered after a time t is given by
where
is the initial angular speed. So, the angle covered after a time t=3.07 s is
where
In our problem, the initial angular speed is zero (the wheel starts from rest), so the angular acceleration is
(b) The wheel is moving by uniformly rotational accelerated motion, so the angle it covered after a time t is given by
where