Question

A ball is thrown vertically upward with a speed of 36.0 m/s.

a) How high does it rise?

b) How long does it take to reach its highest point?

c) How long does the ball take to hit the ground after it reaches its highest point?

d) What is its velocity when it returns to the level from which it started?

Answer 1

a. Using the basic kinematic equation,

v² - u²   = 2as

final velocity will be 0 at the highest point, so v = 0, u= 36 m/s and a = -9.8 m/s²

-(36)² = 2 x -9.8 x h

h = 1296/19.6 = 66.12

∴ h = 66.12 m

b. using the equation, v = u + at

at the highest point v = 0

t = 36/9.8 = 3.67 seconds

∴ t = 3.67 sec

c. It takes same amount of time to travel in both the directions.

so time taken by the ball to reach ground = time taken by the ball to reach its highest point = 3.67 sec

∴ t = 3.67 sec

d. At the highest point velocity is zero, i.e., initial velocity u = 0

v² - u²   = 2as

v² - 0 = 2x 9.8 x 10

∴ v = 14m/s

Please rate my answer, good luck...