How to Solve Some Gravity Formulas
At this point, you know these formulas:
|
D =1/2 gt2 (Calculates Dropping Distance) |
V = gt (Falling velocity) |
|
HD = vt (Calculates Horizontal Distance) |
Time = |
Remember
all objects accelerate at 9.81 meters/sec2.
Directions: Read each question below. Decide which
formula to use. Write the appropriate formula in the space provided. In
order to receive credit, you must show your work by plugging numbers under the formula.
Solve the formula, write the appropriate units, and circle your answer.
A man in a jeep climbs a hill and drives off
a cliff at a rate of 25 meters/second.
1) What distance in meters does the
jeep drop if it takes the vehicle 3 seconds to hit the ground below?
There is no air resistance.
|
Distance |
= |
1/2 g |
X |
t 2 |
|
|
= |
1/2 (9.8) |
X |
3 2 |
|
|
= |
4.9 |
X |
9 |
|
|
= |
44.1 meters |
||
2) How many meters away from the base
of the cliff will the jeep land if its horizontal velocity is 25
meters/second and it takes 3 seconds to hit the ground? There is no air
resistance.
|
Horizontal Distance |
= |
v |
X |
t |
|
|
= |
25 |
X |
3 |
|
|
= |
75 meters |
||
3) What is the falling velocity of the
jeep (in meters/second) as it hits the ground if it falls for 3 seconds?
There is no air resistance.
|
Velocity |
= |
g |
X |
t |
|
|
= |
9.8 |
X |
3 |
|
|
= |
29.4 meters/second |
||
4) How many seconds would it take the jeep
to drop to Earth if it fell out of a plane a distance of 4000 meters? There is
no air resistance.
|
Time = |
||
|
|
= |
2 X 4000/ 9.8 |
|
|
= |
8000/9.8 |
|
|
= |
816.3 |
|
|
|
Get square root of 816.3 |
|
|
= |
28.6 seconds |