i have a quesiton

The displacement of a particle in ft moving vertically is given as h(t) = 80t - 8t2 after t seconds. Using Calculus techniques (that is, critical points, derivative tests, etc.) determine the following: a. How high will the particle go? b. What is its velocity at a height of 128 ft above the ground on its way up? c. What is its acceleration at any time during its flight? d. When does the particle hit the ground