Velocity problems: A stone is thrown vertically upwards at 24.5m/s from a point on...

[Kitimbo]

A stone is thrown vertically upwards at 24.5m/s from a point on the level with but just beyond a cliff ledge. Its height above the ledge t s later is 4.9t(5-t)m.If its velocity is v m/s,differentiate to find v in terms of t.
(a)when is the stone at the ledge level?
(b)when is the stone momentarily at rest?what is the greatest height?

 

[HallsofIvy]

You have repeatedly posted problems without showing any attempt yourself to solve them! Is that because you really have no idea what the question is asking or because you just don't want to do the work yourself? Here you are given a formula for the height of an object above a shelf and are asked for the time at which the object is "at the shelf". Do you not understand that this means that the "height above the shelf" is 0? Can you not set the formula equal to 0 and solve the resulting quadratic equation? Which has already been factored for you! Are you saying that. in a Calculus class, you can not solve an equation of the form Ax(5- x)= 0? If so then you need to talk to your teacher. Do you know what "momentarily at rest" means?

 

[Kitimbo]

You got rude on me for nothing.
Am a student who have just joined A level so the questions I post no one have ever taught me them.The teacher just enters the class and solve one simple question and he leaves.So its on me to look for a little bit tough questions to do them if I want to excel. Its not even home work,its my personal work.I want to be good in math in fact I solve 50 questions everyday so any question which I can't solve is what I post here.In fact I teach my self from textbooks.
Am a fast learner infact am one of the best in class

 

[JeffM]

No one got rude. Someone was honest with you. The rules are that you show your work or at least explain what you think may be a way to attack the problem. We do not know what you know, what you have tried, etc. UNLESS YOU TELL US.

We don't know whether you know how to differentiate. So we have no clue where you got stuck. You are asking for free help. Try being courteous and following the rules.

 

[stapel]

the questions I post no one have ever taught me them.

Then you need to consider hiring a qualified local tutor who can provide you with the months or years of missing material. Unforunately, that process cannot be replicated in a forum posting. (And doing a homework exercise for you wouldn't teach you the general content, anyway.)

Good luck!