A dog mass with 14 kg has a kinetic energy of 135.5 J.What is the speed of the dog?
2 answers:
Answer:
The speed of the dog is 4.39 m/s.
Explanation:
Given that,
Mass of the dog, m = 14 kg
Kinetic energy of the dog, E = 135.5 J
To find :
The speed of the dog
Solve :
The energy possessed by an object due to its motion is called ts kinetic energy. Its formula is given by :
v = 4.39 m/s
Therefore, the speed of the dog is 4.39 m/s.
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We can use the law of conservation of energy to solve the problem.
The total mechanical energy of the system at any moment of the motion is:
where U is the potential energy and K the kinetic energy.
At the beginning of the motion, the ball starts from the ground so its altitude is h=0 and therefore its potential energy U is zero. So, the mechanical energy is just kinetic energy:
When the ball reaches the maximum altitude of its flight, it starts to go down again, so its speed at that moment is zero: v=0. So, its kinetic energy at the top is zero. So the total mechanical energy is just potential energy:
But the mechanical energy must be conserved, Ef=Ei, so we have
and so, the potential energy at the top of the flight is
The total mechanical energy of the system at any moment of the motion is:
where U is the potential energy and K the kinetic energy.
At the beginning of the motion, the ball starts from the ground so its altitude is h=0 and therefore its potential energy U is zero. So, the mechanical energy is just kinetic energy:
When the ball reaches the maximum altitude of its flight, it starts to go down again, so its speed at that moment is zero: v=0. So, its kinetic energy at the top is zero. So the total mechanical energy is just potential energy:
But the mechanical energy must be conserved, Ef=Ei, so we have
and so, the potential energy at the top of the flight is