Post by: Tea.bag on March 14, 2008, 05:32:35 pm
i just wanted to how write a good report on an experiment for physics. Any help will be appreciated.
Post by: sammy_g on March 15, 2008, 12:43:44 pm
[IMG]http://img246.imageshack.us/img246/3773/physicspracreporths6.th.jpg[/img]
Post by: Tea.bag on March 18, 2008, 04:17:35 pm
hey can any of you smart people explain to me...
If we drop a ball from different heights. why does the impact time with the ground increase?
Explain in terms of physics
Post by: Mao on March 18, 2008, 06:04:36 pm
what happens is, the kinetic energy is larger when dropped from higher height, meaning a higher momentum.
The higher momentum means a higher impulse (change in momentum)
But the normal reaction force is equal and opposite of gravity, and hence is also constant
therefore according to the impulse equation:
where force is constant, higher impulse (momentum) means longer time =D
Post by: Tea.bag on March 18, 2008, 06:22:15 pm
Post by: Collin Li on March 18, 2008, 06:42:37 pm
but why is the bounce height less than the original height?
It's not an elastic collision. You heard the ball bounce right? That's sound energy that was previously kinetic energy... and it's not going to be kinetic energy for the ball on the way up, now that it's gone to your ears.
There's also air resistance, and lots of other possible losses of energy (heat, light, etc.) although they are not all applicable in the case of a bouncing ball.
Post by: Mao on March 18, 2008, 06:58:07 pm
however, the mass of earth is so huge that the little velocity earth bounce away with makes up for the observable loss in kinetic energy/momentum
Post by: Tea.bag on March 29, 2008, 05:34:40 pm
Post by: Mao on March 29, 2008, 05:55:34 pm
notes i have uploaded:
http://notes.vcenotes.com/?step=download&action=feedback&id=36
and this thread:
http://vcenotes.com/forum/index.php/topic,2172.0.html
hopefully that will sort out some confusions
Post by: Tea.bag on March 31, 2008, 09:55:47 am