Posted by Sasha on Thursday, November 12, 2009 at 8:12pm.
a 145g baseball is dropped from a tree 13.0m above the ground. with what is the velocity of the baseball at the ground after it falls 13.0m? B. If it actually hits the ground with a speed of 8.0o m/s, what is the average force of air resistance exerted on it?

physics  drwls, Thursday, November 12, 2009 at 8:20pm
Use conservation of energy to calculate the velocity at the ground with no friction.
V = sqrt (2 g H) = 15.97 m/s
If there is a lower velocity of 8.0 m/s, which is about 1/2 of the frictionless value, than about 3/4 of the available potential energy has been lost to friction.
Friction energy loss = (3/4)*M g H = ?
For the average force, solve
(friction energy loss)= (average force) x (13.0 m)
Answer This Question
Related Questions
 physics  A 149{\rm g} baseball is dropped from a tree 12.0 m above the ground...
 college physics  A 147 g baseball is dropped from a tree 12.0 m above the ...
 Physics  A 140 g baseball is dropped from a tree 15.5 m above the ground. With ...
 physics  A 143g baseball is dropped from a tree 13.0 m above the ground. With ...
 Physics  I'm not sure how to do this problem A 145g baseball is droppexc from ...
 Precalc  Fred hits a baseball 3 ft above ground at a velocity of 100 ft per sec...
 physics  a rock is dropped from a height of 20m above the ground when it hits ...
 physics  a rock is dropped from a height of 20m above the ground when it hits ...
 Math 10  Hello, Is there easiest and simplest way to do this question? "A ...
 physics  a .140 kg baseball is dropped from rest from a height of 2.2m above ...
More Related Questions