A 0.2 kilogram baseball is thrown vertically downwards towards to the same horizontal floor. The baseball possesses an initial velocity of 30 meters per second. The height is 10.00m.

(A) Calculate the POTENTIAL GRAVITATIONAL ENERGY and KINETIC ENERGY of the baseball at the moment of release from the thrower's hand.
Is Potential Energy=19.62J?and Kinetic energy=90J?

(B) Calculate the POTENTIAL and KINETIC ENERGY of the baseball at the moment of impact at the floor.
Is Potential Energy=0J? and Kinetic energy=109.62J?

I am not really sure about the answers. Please help check.

(A) Yes to both questions, assuming the zero for potential energy is taken as the ground elevation. Potential energy can be defined as zero anywhere. It is only the changes in P.E. that matter in the energy and motion quations

(B) Yes again. You seem to have a good grasp of the situation.

hi 2007

hello 2007

To calculate the potential and kinetic energy at different moments, we can use the formula for potential energy (PE) and kinetic energy (KE).

(A) At the moment of release, the potential energy is equal to the gravitational potential energy:

PE = mgh

where m is the mass of the baseball (0.2 kg), g is the acceleration due to gravity (9.8 m/s^2), and h is the height (10.00 m).

Substituting the values into the formula:

PE = (0.2 kg)(9.8 m/s^2)(10.00 m)
= 19.62 J

Therefore, the potential energy at the moment of release is 19.62 J.

Next, the kinetic energy at the moment of release can be calculated using the formula:

KE = (1/2)mv^2

where v is the initial velocity (30 m/s).

Substituting the values into the formula:

KE = (0.5)(0.2 kg)(30 m/s)^2
= 90 J

Therefore, the kinetic energy at the moment of release is 90 J.

(B) At the moment of impact with the floor, the potential energy is zero because the height is taken relative to the floor. Any change in height is already accounted for by the potential energy at the moment of release.

So the potential energy at the moment of impact is 0 J.

The kinetic energy at the moment of impact can be calculated in the same way as before:

KE = (1/2)mv^2

Substituting the values into the formula:

KE = (0.5)(0.2 kg)(30 m/s)^2
= 90 J

Therefore, the kinetic energy at the moment of impact is 90 J.

To summarize:
(A) Potential energy at release = 19.62 J and kinetic energy at release = 90 J.
(B) Potential energy at impact = 0 J and kinetic energy at impact = 90 J.

So, your answers are correct.