
#1
Sep1410, 08:25 PM

P: 2

1. The problem statements, all variables and given/known data
1. a 100m long train accelerates uniformly from rest. If the front of the train passes a railway worker 150m down the track at a speed of 25m/s, what will be the speed of the last car as it passes the worker? 2. a hot air baloon is rising up with a constant velocity of 4m/s. As the balloon reaches a height of 4m above the ground the balloonist accidentally drops a can of pop over the edge of the basket. How long does it take the pop can to reach the ground? 3.a stone is dropped from the roof of a high building. a second stone is droped 1s later. How far apart are the stones when the second one reached the speed of 23m/s? 3. a rock is dropped from a seacliff and the sound of it stirking the ocean is heard 3s later. If the speed of sound is 330m/s, how high is the cliff? 2. Relevant equations These are the equations we were given to solve the questions: (it might look messy, f is final and t is time) Vf^2=V1+2ad Vf=V1+at d=V1+1/2at^2 d=Vft1/2at^2 d=(V1+Vf/2)t honestly i tried doing these, but i just dont get it! 



#2
Sep1410, 08:56 PM

P: 14

1. 150/25 = 250/x
x = 41.6666667m/s 2. this one is weird. can't help. are you sure you copied all the data? 3. vf^2=vi+2ad 23^2=0+2(9.8)d d=27 m (stone 1) d = (vi+vf/2)t 27 = (0+ 27/2)t t=2 seconds( the first stone reached 27m in two seconds) 2s 1s = 1s so we want to calculate the position of stone 2 at one seconds so d = vi + .5at^2 d = 0 + .5*9.8*1^2 d = 4.9m 21  4.9 = 22.1m difference 4. 3s * 330m / 1s = 990 m have no clue if any of these are correct. please check my work guys 



#3
Sep1510, 09:07 PM

P: 2

Hey thanks for the help, the first and third make sense.. yea it know the second is weird but i read the question over and thats what it says. the 4th one is way off lol, it was a pretty long solution that came to a heights of h=4.9(2.9)^2



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