Using F = Ke
F = 39200×(25÷100) = 39200×0.25
F= 9800N
For this, you need the v-squared equation, which is v(final)² = v(initial)² + 2aΔx
The averate acceleration is thus a = (v(final)² - v(initial)²) / 2Δx = (20² - 15²) / 2(50) = 175 / 100 = 1.75 m/s²
So the average acceleration is 1.75 m/s²
The earth obviously because it is on Earth like we are and it has the same gravital properties. It falls when you drop it and rises when you pick it up