Question

A baseball is hit 3 feet above the ground at 80 feet per second and at an angle of with respect to the ground. Find the maximum height. Round your answer to the nearest integer.

Answer 1

53

Explanation:

i used an angle of 45 degrees.

Distance from ground = 3feets

Angle = 45⁰

U is the initial velocity = 80ft/sec

g = 32

The question wants us to vfind maximum height

We have

r(t) = (80cos45⁰)ti + [3 + 80sin45⁰]t - 0.5(32)t²

We know cos 45 is also sin45 = 1/√2

r(t) = (40√2)ti + [3+40√2]t - 16t²

When we differentiate with respect to t:

r'(t) = (40√2)i + (40√2 - 32t)

= 40√2 =32t

t = 40√2/32

t= 20√2/16

We put the value of t into (3 + 40√2)t -16t²

When we substitute and simplify this we have

3 + 56.57 + 1.77 -16 +8

= 53.34

Which is approximately 53.