Equations of motion under constant acceleration questions.. (1 Viewer)

[+GriM ReApeR+]

Solve using the equations:
v=u+at
s=ut+(1/2)at^2
v^2=u^2+2as

1. A stone is let fall from a tall building and 1 second later another stone is projected vertically downwards of 20m/s. When will the second stone overtake the first?

2. An object falling in a vertical line passes a window 3m high in 1/6 second. Find the distance above the top of the window from which the object was let fall?

Thanks

 

[withoutaface]

1. find the vertical flight equations of both (remembering that one is 't-1') and equate them

2.

a= gt_________a+3=g(t+1/6)

and solve them simultaneously

 

[CrashOveride]

these sound like from couchman?

1. Let the first time be 't' and the projected stone t-1. Use the s= to equate the two remembering the first stone has u=0.

2. Use s= for the portion of the journey past the window. This yields u. Now use v=u+at for the journey from the point of release to top of window. remembering in this case, u=0, u know what v and a is, thus u have the time t to drtop from the point to top of window. Now shove that backj into s= knowing u=0 and a and also t, u will get your s value.

 

[+GriM ReApeR+]

these sound like from couchman?

yup...that book has all those really hard questions

 

[withoutaface]

yup...that book has all those really hard questions

If you want some fun then look at the extension questions from cambridge

 

[+GriM ReApeR+]

oh yea...they're bad too

 

[CrashOveride]

Were u being sarcastic about couchman? Coz if u wern't....

 

[+GriM ReApeR+]

pfftt...oh yea I just loovvee those questions....
no, I'm being sarcastic, seriously...I hate maths (especially couchman ones)

 

[CrashOveride]

I was meaning to say, couchman is like.... Don;t use it man...its too easy just go for past papers now anyway.