Question

During a fireworks display, a shell is shot into air at an initial speed of 70 m/s at Angie of 75above the horizontal. The shell ignites once it reaches its highest point. What was its velocity when it reached highest point? answer in meters per second

Answer 1

The 70-m/s velocity vector has two components: horizontal and vertical. The vertical one changes due to gravity. The horizontal one is constant if we ignore air resistance. Thus, at the highest point, since the vertical component is zero, the entire velocity vector will be represented by its horizontal component:

$$v_\text{at max. height}=v_h=v\text{ cos}75°,\\ v_\text{at max. height}=70\text{ cos}75°=18\text{ m/s}.$$