3. Daniel stands on a bridge over a river. He drops a coin and notes that the coin takes 3 s to reach the river below.
1 answer:
Answer:
<em>45 m</em>
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Explanation:
Initial velocity of the coin = 0 m/s (since he dropped it from his hands)
time spent in falling - 3 sec
distance s = ?
using
s = ut + g
where
s is the distance the stone fell
u is the initial velocity
t is the time spent falling
g is acceleration due to gravity = 10 m/s^2 (positive downwards)
substituting values, we have
s = (0 x 3) + (10 x
)
s = <em>45 m</em>
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Answer:
P = 251,916.667 W
Cost = 2,267.25 cents
Explanation:
To solve this question we will use the Work Energy Theorem, which is
Where
= Change in Potential Energy
= Change in Kinetic Energy
Change in Potential Energy
Where
= Initial Potential Energy
= Final Potential Energy
= Mass of System = 10,000 kg
= Acceleration due to gravity = 9.81 m/s
= Initial Height = 0
= Final Height = 30 m
Inputting the values we get the answer for
Change in Kinetic Energy
Where
= Initial Kinetic Energy
= Final Kinetic Energy
= Mass of System = 10,000 kg
= Acceleration due to gravity = 9.81 m/s
= Initial Velocity = 0 m/2
= Final Velocity = 4 m/s
Inputting the values we get the answer for
Total Work
Inputting the values
a) Finding the useful Power Output
Where
= Power Output
= Work Done = 3,023,000J
= Time = 12s
Inputting the values
P = 251,916.667 W
b) Finding the Total Cost
Cost = $0.0900 x P/1000
Cost = $0.0900 x (251,916.667/1000)
Cost = $22.67 or 2,267.25 cents