Step 1: Find the acceleration We know the final speed v=18m∕s, the starting speed u=0, and the height h=20m. Use the formula: v2=u2+2ah Put the values in: 182=02+2a×20 This gives: a=‌
18×18
2×20
=8.1m∕s2 Step 2: Find the time taken Use the formula: v=u+at Plug in the numbers: 18=0+8.1×t Solve for t : t=‌
