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Thread ID: 108982 2010-04-19 07:25:00 Quick question, Physics? Metla (12) PC World Chat
Post ID Timestamp Content User
878089 2010-04-19 07:25:00 300kg mass, traveling at 100km/h, if it hit an object what would its weight register at? Metla (12)
878090 2010-04-19 07:34:00 depends on the mass of the object its hitting doesnt it?

300x277.77m/s = 83331 (momentum = mass x velocity) i think

its been a while since college:stare:
GameJunkie (72)
878091 2010-04-19 08:19:00 Ah, you got only the first half, GameJunkie

Metla is asking for impulse

Impulse = Change in Momentum / time

Let's say the object bounced off the target and resumes its motion at a 180 degree angle at a speed of 10km/h:

Momentum towards = 83331
Momentum away = 8333.1

Change in momentum = 82497.9 kg m/s

To determine impulse:
Let's say it takes one second for the momentum to change its vector:
Impulse = Change in momentum / time
= (82497.9 kg m / s) / 1 s
= 82497.9 kg m s^(-2)
= 82497.9 Newton (www.daviddarling.info)
= ....... (I'm stuck)
Renmoo (66)
878092 2010-04-19 08:24:00 I'm what?:waughh: Metla (12)
878093 2010-04-19 08:24:00 I thought Metla actually wanted the Kinetic energy. Sweep (90)
878094 2010-04-19 08:35:00 Impact force.

From what I can gather the attached pic is the formula, means nothing to me though.
Metla (12)
878095 2010-04-19 09:11:00 Force = change in impulse divided by change in time. ([velocity final - velocity initial] over [time final - time initial])

So the force is what you're after. (Weight is not equal to mass.)

Let's see... Assuming it stops, (360 - 0) / (tf - ti) {100km/h = 360 metres per second}

We still need to know how quickly it stopped.
pcuser42 (130)
878096 2010-04-19 09:27:00 Impact force.

From what I can gather the attached pic is the formula, means nothing to me though.

Looks more like a music score sheet
gary67 (56)
878097 2010-04-19 09:32:00 Looks nothing like sheet music :lol: pcuser42 (130)
878098 2010-04-19 09:32:00 F = ma where a = v/t The well-known Force equals Mass times Acceleration
therefore
Ft = mv
re-ordering
F = mv/t
thus as t (time of impact) tends to 0 (zero) F tends to infinity, hence before you drop your precious iPhone onto the concrete pavement wrap it in a spongy cover to increase the time of impact away from zero and thus decrease the impact (F).
zqwerty (97)
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