Melody

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यूजर का नामMelody
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Melody  11 Feb 2022
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Good evening everyone,
There were lots of great questions today. Good thing so many of you were helping me answer them.
These answers were provided by Crass, ezom , Alan, Rom, guest, Thatmathguy, anonymous_4481, and unknown,
Unknown provided a few top quality answers, it would be really great if you joined us officially and took a title more worthy of your contributions.

A guest by the name of 23232323.. posted on the end of an unpleasant thread. 2323 politely explained that this was a children's site and the language and content was not appropriate. There were no more unpleasant posts after this. Thank you 2323..
My normal policy for this type of behaviour is to ignore the post. People are looking for a reaction and if they are ignored they soon get bored and go away. However, i am sure that some people just arn't thinking and an explaination such as 2323.. gave is all that is needed to improve the behaviour. This time it appeared to have been successful. So, once again,thank you. 232323.. Why don't you join us properly 2323. There are some good advantages. See the post titled " Become a member - Why would you want to." We would all like you to join

I did a probability post today and I am always a tad unsure of my ability with these. I believe the method is correct though there could easily be a careless error or 2.
Would someone with lots of probability confidence take a look please. If you do check it just add a checked post on the end of the thread. That would be really good and then I can delete this paragraph. Thank you.
http://web2.0calc.com/questions/compund-events

That is it for the day.
Thanks everyone
Melody.
28 Feb 2014
 #2
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tannawirsch:

Okay, so I suddenly realized Physics isn't the easiest subject to learn but I have so much fun learning it! (but now I am stuck)

1. It was recorded that a Jaguar left skid marks which were 290 meters in length. Assuming that the Jaguar skidded to a stop with a constant acceleration of -3.90 m/s^2 , determine the speed of the Jaguar before it began to skid.
*For this question I couldn't figure out what equation to use*
Make a list of what you have
u = initial velocity = unknown
v = end velocity = 0
a = -3.9 m/s2
s = distance travelled = 290m
Look for a formula that has those things
v2 = u2 +2as
0 = u2 + 2*-3.9*290
u2 = 2262
u = 47.56 m/s

It has been a life time since I have done these problems but I think that is correct.

and same as with the following question:

2. A dragster accelerates to aspeed of 112m/s over a distance of 398m. Determine the acceleration(uniform) of the dragster.

Also, I need to go over a couple of questions to make sure I got them right.

1. A car traveling along a straight road ata a constant velocity of 20m/s. The driver depresses the acceleration and the velocity of the car changes to 35m/s in the next ten seconds. Calculate the acceleration of the vehicle.

V₁ = 20m/s
V₂ = 35m/s
∆T = 10s
A = ?

A = V₂ - V₁ / ∆T
= (20 - 35 / 10)
= 16.5 m/s^2

2. Calculate the ground velocity of a small boat that can travel 2 m/s in still water but heading East in a river that has a current of 0.5 m/s [S].

Find the direction: tan θ = 0.5 / 2
tan θ = 14˚
V2 = ( 2 m/s )^2 + ( 0.5 m/s )^2
= 4.25
V = √4.25 = 2.06



This is another site (besides rom's one) that might help.
http://www.physicsforidiots.com/dynamics.html
28 Feb 2014