Robbie Knievel ride On May $20,1999,$ Robbie Knievel easily cleared a narrow part of the Grand Canyon during a world-record-setting long-distance motorcycle jump - 69.5 $\mathrm{m} .$ He left the jump ramp at a $10^{\circ}$ angle above the horizontal. How fast was he traveling when he left the ramp? Indicate any assumptions you made.