Saturday

August 2, 2014

August 2, 2014

Posted by **Kate** on Tuesday, August 9, 2011 at 2:57pm.

I started off with 55cos(44)=40

then I made an equation

40t-16(t)=2.5 seconds?

I feel like I did this wrong because I didn't add 3 feet anywhere

or do I add 3 in to 55cos(44) giving me an answer of 2.6

- Precalculus -
**MathMate**, Tuesday, August 9, 2011 at 5:09pmYes, the 3 feet are important.

You can consider the datum (y=0) at 3' from the ground, and the ground is therefore at -3 feet.

The vertical initial velocity, vy, is u*sin(θ), so it gives

vy=55sin(44°)=38.21 approx.

The (vertical) distance travelled is given by:

S=vy*t-(1/2)gt²

where

S=-3 (ground)

vy=55sin(44°), and

g=32.2 ft/s²

Solve for t.

I get -0.08 and 2.45 s.

**Related Questions**

Trigonometry - A ball is thrown with an initial velocity of 65 feet per second, ...

algebra - y=(v/u)x+(g)/(2(u^2))*x^2 where y is the object's vertical distance (...

physics - A ball is thrown with an initial velocity of 20 meters per second at ...

algebra - An object is released into the air at an initial height of 6 feet and ...

Precalculus - When a projectile leaves a starting point at an angle of elevation...

physical - A ball is thrown from the window of a high-rise building with an ...

phy - A ball is thrown from the window of a high-rise building with an initial ...

ap calculus - The height s of a ball, in feet, thrown with an initial velocity ...

Algebra - THe function h(t)=-16t^2+v0t+h0 describes the height in feet above the...

Algebra - THe function h(t)=-16t^2+v0t+h0 describes the height in feet above the...