How long does it take the stone to reach the bottom of the cliff?
A. In the projectile motion analysis, we get that the velocity of the projectile does not change in the horizontal direction because there is no acceleration present in the horizontal direction.
What is the vertical component of the velocity of the stone as it hits the ground?
B. The vertical component of the velocity changes with time because of acceleration due to gravity.
Given:
The horizontal velocity is
ux=5 m/s
The initial vertical velocity is
u y = 0
The initial height is
h = 78.4m
a):
The horizontal component of the velocity of the stone as it hits the ground is,
vx= ux = 5m/s
Let the final vertical component be vy.
Now, using the third equation of motion,
Now, using the third equation of motion,
v²y= u²y + 2 gh
v²y= 0 + 2 (9.81m/s2 )(78.4m)
vy=39.2m/s
b):
The final speed for the stone as it hits the ground is,
v = √v2x+v2y
v = √(5m/s)²+(39.2m/s)²
v = 39.5m/s
**when you don't understand just look at the picture**
^^
