a small dog is train to jump straight up a distance of 1.2m. how much kinetic energy does the 7.2-kg dog need to jump this high ( the acceleration due to gravity is 9.8m/s2
V^2 = Vo^2 + 2g*d
Vo^2 = V^2-2g*d
Vo^2 = 0-(-19.6*1.2 = 23.52
Vo = 4.85 m/s.
Ek = 0.5m*Vo^2 = 3.6*(4.85)^2 = 11.76 J.
vo^2
CORRECTION:
Ek = 84.672 J.
To calculate the kinetic energy needed for the dog to jump 1.2m, you can use the concept of work-energy theorem. The work-energy theorem states that the work done on an object is equal to the change in its kinetic energy.
First, we need to find the work done on the dog. The work done on an object is given by the formula:
Work = force x distance
In this case, the force acting on the dog is its weight, which is equal to its mass multiplied by the acceleration due to gravity, i.e., 7.2kg x 9.8m/s².
Next, we need to calculate the distance the dog jumps, which is 1.2m.
Plugging in the values, we have:
Work = (7.2kg x 9.8m/s²) x 1.2m
Simplifying, we get:
Work = 84.96J
This value represents the work done on the dog. Now, using the definition of kinetic energy, we know that the work done is equal to the change in kinetic energy of the object:
Kinetic Energy = Work done
Therefore, the kinetic energy needed for the dog to jump 1.2m is 84.96J.