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Stu
13-06-07, 01:24 PM
OK, so what's the time taken to accelerate to 62mph of something dropping in freefall (ignoring wind resistance)
I reckon it's about 5 secs, but can't prove it.

Stingo
13-06-07, 01:28 PM
See here....

Acceleration is the rate of change of velocity of an object.
http://www.mathsrevision.net/alevel/mechanics/Accele1.gif
where a is acceleration, v is the final velocity of the object, u is the initial velocity of the object and t is the time that has elapsed.
This equation can be rearranged to give:

v = u + at
If s represents the displacement of the object, then:

s = ˝ (u + v)t
s = ut + ˝ at2
v2 = u2 + 2as
These equations are true if the acceleration of the body in question is constant (i.e. it doesn’t change over the time period). The units used must be consistent, and the standard units are:
Acceleration: ms-2(or m/s2)
Velocity: ms-1 (or m/s)
Displacement: m
Time: s
The equation which you will need to use depends upon the question.
The Acceleration due to Gravity

If a body is dropped from a height, it will accelerate because of gravity. The acceleration caused by gravity is written as “g”, and is usually taken to be 9.8 ms-2.
Example

A ball is dropped from the leaning tower of Pisa, at a height of 50m from the ground. The ball is dropped from rest and falls freely under gravity. How long will it be before the ball hits the ground?
We know: s = 50, a = 9.8, u = 0 and we want to find t.
The equation connecting these four is s = ut + ˝ at2
So 50 = 0 + ˝ × 9.8 × t2
Rearranging: t2 = 10.20408
t = 3.19…
the time taken is 3.19s (3sf)

sarah
13-06-07, 01:29 PM
OK, so what's the time taken to accelerate to 62mph of something dropping in freefall (ignoring wind resistance)
I reckon it's about 5 secs, but can't prove it.

gravitational acceleration is approx 9.81 m/s^2

hth

Dan
13-06-07, 01:30 PM
Should be about 2.82 seconds ignoring all other factors.

Gravitational acceleration constant is IIRC 9.81m/s/s and 62mph is about 27.71m/s

so acceleration to 62mph = 27.71/9.81 = 2.82 approx.

Is that right?

Baph
13-06-07, 01:30 PM
That depends on how high up you start from, and the mass of the object that you're dropping.

Acceleration due to gravity: http://teacher.nsrl.rochester.edu/phy_labs/Measure_g/Measure_g01.gif
where G is Newton's gravitational constant, http://teacher.nsrl.rochester.edu/phy_labs/Measure_g/Measure_g02.gif is the mass of the earth and r is the distance to the center of the earth. In as much as the radius of the earth is very large compared to laboratory dimensions, an object near the surface of the earth, r is approximately constant and equal to the radius of the earth,http://teacher.nsrl.rochester.edu/phy_labs/Measure_g/Measure_g03.gif

It's possible to experience constant acceleration, if you're "near" the surface of the earth, or the relative mass is "insignificant."

Steve H
13-06-07, 01:32 PM
3.19 secs eh?
All I've got to do is find a cliff and I can personally give a GSXR1
a run for its money. :geek:



No:D comments about doing people a favour please.

Tomcat
13-06-07, 01:34 PM
0-60 : 4 secs silver 03 cbr600


All im interested in mate ;)

Stu
13-06-07, 01:35 PM
Gosh Stingo, you typed that all out by hand in 4 minutes good effort, shame it didn't answer the question! :lol:

Sarah HTH - No I already had that.

I had the 28meters per second & 10 meters per second squared, didn't realise you could just divide one by the other. Thanks

Was reading about Northwind's Veypor giving him a G force of .74 & Jelster ridiculing him for it not being more than 1G.

sarah
13-06-07, 01:38 PM
Gosh Stingo, you typed that all out by hand in 4 minutes good effort, shame it didn't answer the question! :lol:

Sarah HTH - No I already had that.

I had the 28meters per second & 10 meters per second squared, didn't realise you could just divide one by the other. Thanks

Was reading about Northwind's Veypor giving him a G force of .74 & Jelster ridiculing him for it not being more than 1G.

i was too lazy to convert mph to m/s

Filipe M.
13-06-07, 01:41 PM
So does the plane take off or not?

Grinch
13-06-07, 01:42 PM
Free fall is fun... I'd like to do it again.

Baph
13-06-07, 01:45 PM
So does the plane take off or not?
I can undeniably answer that!!

http://forums.sv650.org/image.php?u=4662&dateline=1172588182&type=profile

YES, the plane does take off!

Steve H
13-06-07, 01:45 PM
0-60 : 4 secs silver 03 cbr600


All im interested in mate ;)

'bought the same as an SV though. ;)

Stingo
13-06-07, 01:47 PM
So does the plane take off or not?

No - it transforms into a toilet.:cool: ;) :geek: :smt025 :help:

rigor
13-06-07, 01:49 PM
That depends on how high up you start from, and the mass of the object that you're dropping.

Acceleration due to gravity: http://teacher.nsrl.rochester.edu/phy_labs/Measure_g/Measure_g01.gif


Oops, back of the class Mr Baph ;)

Tomcat
13-06-07, 01:53 PM
'bought the same as an SV though. ;)


shall we discuss top speed ;) !

Filipe M.
13-06-07, 01:54 PM
shall we discuss top speed ;) !

Of Stingos toilet?

Tomcat
13-06-07, 01:55 PM
Of Stingos toilet?

acceleration a little lumpy, but the final flush is always satisfying

Steve H
13-06-07, 02:05 PM
shall we discuss top speed ;) !

O.K. As I understand it it's 70mph. I could be wrong. ;)
I think an SV will do the best part of 130. I am never going to need that, personally. ;)