Question

When a handball strikes a vertical wall, its velocity changes from25 m/s [S15°E] to 30 m/s [S40°W]. Determine the handball’schange in velocity

Answer 1

When a handball strikes a vertical wall, its velocity changes from $25\,\mathrm{m/s}$ [S15°E] to $30\,\mathrm{m/s}$ [S40°W]. Determine the handball's change in velocity.

Solution

$$\begin{array}{l} \left| \overrightarrow {V _ {2}} - \overrightarrow {V _ {1}} \right| = \sqrt {\left| \overrightarrow {V _ {2}} \right| ^ {2} + \left| \overrightarrow {V _ {1}} \right| ^ {2} - 2 \left| \overrightarrow {V _ {2}} \right| \left| \overrightarrow {V _ {1}} \right|} \cos a = \\ \sqrt {2 5 ^ {2} + 3 0 ^ {2} - 2 * 2 5 * 3 0 \cos (3 0 + 1 5)} = 2 1. 5 \,\mathrm{m/s} \end{array}$$

the handball's change in velocity $21.5\,\mathrm{m/s}$ S85°W