The change in the kinetic energy refers to the work done in displacing a body, thus, the change in the kinetic energy of an object refers to the work done on the object.
The correct formula to use is:
W = Initial kinetic energy - Final kinetic energy;
Where, W = change in kinetic energy
Final kinetic energy and initial kinetic energy = 1/2 MV^2
Initial velocity = 15 m/s
Final velocity = 13.5 m/s
Initial mass = 0.650 kg
Final mass = 0.950 kg
W = 1/2 [0.650* (15 *15)] - 1/2 [0.950 * (13.5 * 13.5)]
W = 146.25 - 173.13 = 26.88
Therefore, the change in kinetic energy is 26.88 J.
The negative sign has to be ignored, because change in kinetic energy can not be negative.
<span />
1.1 A. An electric oven with a resistance of 201Ω and a voltage of 220V drwa a current of 1.1 A.
The easiest way to solve this problem is using the Ohm's Law I = V/R.
An electric oven has R = 201Ω, and a drop of voltage V = 220v, solve using I = V/R:
I = 220V / 201Ω
I = 1.09 A ≅ 1.1 A
You do 1000 divide it by 10 which equals 100 W
The fraction of energy that is lost is 25%, it depends how fast the ball was going until it lost 25% of its energy, the gravitational energy was transferred into the kinetic energy that helped the ball bounce back
