SOLUTION: 4. A ball is dropped from rest and allowed to free fall. Assuming acceleration due to gravity is 10 m/s2, after 6 seconds: a) How fast is the ball falling? b) How far h

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: 4. A ball is dropped from rest and allowed to free fall. Assuming acceleration due to gravity is 10 m/s2, after 6 seconds: a) How fast is the ball falling? b) How far h      Log On

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Question 387411: 4. A ball is dropped from rest and allowed to free fall. Assuming acceleration due to gravity is 10 m/s2, after 6 seconds:
a) How fast is the ball falling?




b) How far has it fallen?

Answer by Jk22(389) About Me  (Show Source):
You can put this solution on YOUR website!
a) Speed is acceleration times time : 10m/s^2*6s=60m/s

b) the energy formula is : mv^2/2+mgh=cste =>
at rest : 0
after 6s : mv^2/2+mgh=0 => h = -v^2/2g = -60*60/2/10 = -180m

the ball is 180m lower.

Other calculation : Distance is one half acceleration time squared :

d = gt^2/2 = 10*6*6/2= 180m