PG. 69 #17

A tiger leaps horizontally from a 7.5 m-high rock with a speed of 3.0m/s. How far from the rock will she land?

GIVEN

• Dy=7.5m
• Vx=3.0m/s

Untitled Slide

To find your Dx, you must first find time. Since you are given a Dy, you must find the square root of 2Dy/g.

2(7.5)/9.8
15/9.8
1.53
square root 1.53
t=1.24

Now that you have time, you can find your Dx.
Use the equation, Dx=Vx*t

3.0*1.24=3.72

When the tiger jumps off a cliff with a horizontal velocity of 3.0m/s and the height of the cliff is 7.5, it's distance it travels before it lands is 3.72m.

PG. 69 #21

A ball thrown horizontally at 12.2m/s from the roof of a building lands 21.0m from the base of the building. How high is the building?

GIVEN

• Dx=21.0m
• Vx=12.2m/s

Untitled Slide

To find your Dy, you must first find time. Since you are given a Dx, you must use t=Dx/Vx.

t=21/12.2
t=1.72
Then to find Dy, you must use the equation 1/2gt^2
1/2(9.8)(1.72)^2
Dy=14.5

When a ball is thrown with a horizontal velocity of 12.2m/s and lands 21.0m away, the height must be 14.5m