Recent content by morphine

Homework Statement If a tank holds 5,000 gallons of water which drains from the bottom of the tank in 40 minutes, then Torricelli's Law gives the volume V of water reminaing in the tank after t minutes as V = 5000(1 - t / 40)2, 0 <= t <= 40. The rate at which water is draining from...

Right you are, so I get 16 on the way up or -16 on the way down. Thanks for your help!

OK. 96 = 80t - 16t^2 96 / 16 = (80t -16t^2) / 16 6 = 5t - t^2 y = -t^2 + 5t +6 y = -1(t + 2)(t + 3) soooo t = -2 or -3? I feel like I am going about this the wrong way... Plugging either of those in gets a number above 100.

Not getting anywhere with that, sorry I need another hint. All I've been able to come out with are answers that don't make sense. By the way, it's multiple choice, and the possible answers are: 80, -80, 32, 16, -16 feet/sec

Argh, it's these little things that kill me in math! So the h term becomes 0, so: s'(t) = 80 - 32t But I'm still unclear how I get the velocity at 96 feet. I recognize that the velocity is the slope of the tangent line but... Oh wait 32 would be the slope of that line, correct? So the...

My intermediate step is: (-16t^2 - 32th - 16h^2 + 80t + 80h + 16t^2 - 80t) / h Then I cancel out like terms, factor out the h and cancel it. Then I'm left with s'(t) = -16h -32t + 80. Where have I gone wrong?

Homework Statement If a ball is thrown vertically upward with a velocity of 80 ft/sec, then its height after t seconds is given by s = 80t - 16t2 . What is the velocity of the ball when it is 96 feet above the ground on its way up? Homework Equations The Attempt at a Solution...

Awesome now I see. Thanks for the help Mark and dacruick. Ill probably have a few more questions over the next few hours.

OK, I did that, and assuming my algebra was right I got 3t2 - 9t - 7 And here I'm stuck again. Do I just set that equal to 5 and solve?

Homework Statement (Sorry I don't know how to insert nice looking equations) If the position function of a particle is given by s = t3 - 4.5t2 - 7t, t >= 0 , the particle reaches an instantaneous velocity of 5 m/sec when t = 1 2 3 4 5 Homework Equations The Attempt at a...

I may be wrong, but I thought gravitation could be described either by gravitons or by general relativity (curvature of space-time).

So I just signed up to post on this topic, and I'm sorry to swing it into a philosophical direction, but this seems the best way to make the question feasible. In reference to the mind-body problem, Descartes proposed that the mind exists in time and not in space. The mind has no mass and no...