A ball of mass 100 g is projected with velocity \(20\mathrm{m}/\mathrm{s}\) at \(60^\circ\) with horizontal. The decreas…

\(K{E}_{\text{initial }}=\frac{1}{2}m{v}^{2}\\ K{E}_{\text{initial }}=\frac{1}{2}\times 0.1\times (20{)}^{2}=20J\\ K{E}_{\text{final }}=\frac{1}{2}m{v}_{x}^{2}\\ K{E}_{\text{final }}=\frac{1}{2}\times 0.1\times (10{)}^{2}=5J\text{ Decrease in Kinetic Energy }\\ \Delta KE=K{E}_{\text{initial }}-K{E}_{\text{final }}\\ \Delta KE=20-5=15J\)