Solve the Golf Ball Problem: Time and Speed Calculations | 2-D Homework

[vietmon]

Homework Statement

A golf ball rolls off a horizontal cliff with an initial speed of 11.2 m/s. The ball falls a vertical distance of 15.2 m into a lake below.

(a) How much time does the ball spend in the air?
(b) What is the speed v of the ball just before it strikes the water?

y = -15.2m
Vox = 11.2 m/s
Voy = 0
ay = -9.8 m/s^2

The Attempt at a Solution

a) y = Voy t + 1/2 ay t^2
-15.2 = 0 + 1/2(-9.8) t^2
t^2 = 3.10
t = 1.76 s

need help working out part b

 

[hage567]

There will be two components to the final velocity (horizontal and vertical). You need to find both and add them (as vectors).

 

[baba89]

b) To solve for the speed v just before the ball strikes the water, we can use the equation v = v0 + at, where v0 is the initial velocity and a is the acceleration due to gravity. Since the ball is falling, the acceleration due to gravity is -9.8 m/s^2.

Substituting in our values, we get:

v = 11.2 m/s + (-9.8 m/s^2)(1.76 s)
v = 11.2 m/s - 17.25 m/s
v = -6.05 m/s

Therefore, the speed of the ball just before it strikes the water is approximately 6.05 m/s.