Answer:
The ball takes 5s to reach the ground
Explanation:
in order to solve this problem we use the kinematics equation with gravity as acceleration:
we replace the values
We solve this quadratic equation:
t=5s
t=-6s (this solution has not physical sense)
Answer:
t = 17658 s = 294.3 min = 4.9 h
Explanation:
The general formula for power is:
where,
P = Power of the Motor = 50 KW = 50000 W
W = Work Done by Motor = Change in P.E of Water = mgh
g = acceleration due to gravity = 9.81 m/s²
m = mass of water = ρV
h = depth of water = 180 m
ρ = density of water = 1000 kg/m³
V = Volume of Water = 500 m³
t = time taken = ?
Therefore,
<u>t = 17658 s = 294.3 min = 4.9 h</u>
Kinetic energy: the energy of motion
Work: the change in kinetic energy
Power: the rate of work done
Explanation:
The kinetic energy of an object is the energy possessed by the object due to its motion. Mathematically, it is given by:
where
m is the mass of the object
v is its speed
The work done an object is the amount of energy transferred; according to the energy-work theorem, it is equal to the change in kinetic energy of an object:
where
is the final kinetic energy
is the initial kinetic energy
Finally, the power is the rate of work done per unit time. Mathematically, ti can be expressed as
where
W is the work done
t is the time elapsed
Learn more about kinetic energy, work and power:
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