Monday
October 20, 2014

Homework Help: Physics

Posted by Liza on Saturday, June 23, 2012 at 9:41am.

An object is released from rest at height h above the surface of the Earth, where h is much smaller than the radius of the Earth. It takes t seconds to fall to the ground. At what height should this object be released from rest in order to take 2t seconds to fall to the ground?
--------------------------------------
Solution: We need to find the connection between the height and time. With “down” positive, so a=g is positive, and with v0 = 0, distance = (1/2) at^2 ? h = (1/2)gt^2 ? h = t^2. Therefore, if we double t, h must increase by a factor of 2^2 = 4.
--------------------------------------
My Question: I don't understand how they are able to just equate h with t^2 (h=t^2). Then say that the answer is 4h. I thought the answer would be 2gh. But then why is it that gravity isn't included in the final answer?

THANKS!

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

Physics - 1.) The earth's radius is about 3956.52 mi. An object that has a mass ...
physics - n object is dropped from rest from a height 5.8 × 106 m above the ...
physics - If the change in the value of 'g ' at a height 'h ' above the surface ...
Physics - a. 2 objects each of mass 200 kg and 500 kg are separated by 50 cm. ...
Algebra - The gravitational force between an object & the Earth is inversely ...
University Physics (Cal-Based) - Calculate the velocity of a 20kg object that is...
earth - A particle weighs 120 N on the surface of the earth. At what height ...
physics - when an object is 100m above the surface of earth. The earth's ...
phys - An astronaut drops an object from rest (relative to the planet) on a ...
MATH - Can someone please help me with the following question. 1) The weight of...

Search
Members