Monday

March 30, 2015

March 30, 2015

Posted by **Rachel** on Thursday, January 31, 2013 at 1:13am.

- calculus 2 -
**Reiny**, Thursday, January 31, 2013 at 8:46amshould have been g = -32

then

v = -32t + c, but when t = 0 , v = 0 , so c = 0

we have v(t) =-32t

then

a(t) = -16t^2 + k, when t = 0 , s = 400 , so k = 400

so our distance equation is

s(t) = -16t^2 + 400

when it hits the ground, s = 0

0 = -16t^2 + 400

16t^2= 400

t^2 = 25

t = 5

which was given, and is correct

if we didn't know the acceleration, let it be a

our distance equation would have been

s(t) = (a/2)t^2 + 400

at half the time, t = 2.5

0 = (a/2)(6.25) + 400

a/2 = -400/6.25

a = -800/6.25 = -128 ft/sec^2

**Answer this Question**

**Related Questions**

Physics - From the top of a tower is an object with mass 25 kg which is lowered ...

Physics - An object is allowed to fall freely near the surface of an unknown ...

Applied Calculus - Suppose that an object is thrown down towards the ground from...

MATH - The height h in feet of an object after t seconds is given by the ...

Science - My mother in law falls from a 200m cliff. Answer the following. a. ...

Calc B/C - Assume no air friction and that the acceleration due to gravity is 10...

precalculus - The acceleration acting on a falling object due to gravity varies ...

Check Math - Old Isaac took a little nosedive from his perch on Mrs. Cohen’s ...

Physics - From the top of a tower is an object with mass 25 kg is lowered at ...

physics - acceleration due to gravity questions when an object is dropped from a...