please help!!! i'm having trouble with this physics problem...i just need someone to point me in right direc

Question

an object of mass m on a string is whirled with increasing speed in a horizontal circle. when the string breakds, the oject has speed v (sub knot) and the cricular path has radius R and is a height h above the ground. neglect air friction.

express in terms of h, v sub knot, and g:
time required for the object to hit the ground after the string breaks
horizontal distance traveled from the time string breaks until it hits the ground
the speed of the object jsut before it hits the ground

then:
determine the tension in the string just before the string breaks

i'm not looking for people to solve it for me, i just need some help to derive the correct equation to solve for the problems... please help!

Answer 1

The first part's the easy part.

The time for the object to hit the ground is...

h=(1/2)gt^2
use this formula, and solve for t.

Now, you know the Vx of the object when in is released. Vx remain the same... you should realize this. in this question, Vx=v
so, to find the distance, use the following equation

d=vt
and replace t with whatever you got in the first part.

to get the speed of the object before it hits the ground, you first need to know the Vy.
in this case,
Vy=gt
Once again sub you answer for t into this equation.

For total speed, however, you need to use Pythagoras' theorem

(Speed)^2=(Vx)^2+(Vy)^2

You should be able to figure it out from there.

Now, for the tricky part. finding the tension in the string
First, find acceleration.

a=(v^2)/R

F=ma
so, T=m[(v^2)/R]

You should understand where I am getting all of these equations from and how to use them. If not, I suggest some review of your textbook.

I hope I helped.

Answer 2

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