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Mechanics M1: Post your doubt here

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so -F = ma
-0.12 = 0.15a
a= -0.8 m/s^2
v=u+at
v=3+(-0.8x2)= 1.4 m/s (velocity it arrives at Y)
at Y k.E = 0.5x0.15x1.4x1.4 = 0.147 J
it loses 0.072 J so k.E at Z = 0.147 - 0.072 = 0.075 J
0.5x0.15x(v^2) = 0.075
v = 1 m/s
since it is in the opp direction velocity becomes -1 m/s
at Z v= o
using v=u+at
0 = -1 + 0.8t
t = 1.25 s
it already took 2s to reach y
therefore total time taken = 2+ 1.25 = 3.25 m/s

thanks but do u know how the curve looks like?
 
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Help me its quite urgent
View attachment 16720
First of all analyze the question this is hell of a question trust me
we hve to build two equation then solve the simultaneously (always consider this option if you cannot figure out the question)
so
the K.E at B =Mgh
mg(H-2.2)=1/2 x m x Vb

And then consider Whole journey from X till ground

mgH=1/2 x m x(2.55Vb)^2 Vg/Vb=2.55 so (speed at the ground)Vg=2.55^2

elimintate Vb by
1/2 x m xVb^2 =mg(h-2.2)
making Vb^2 the subject we get
Vb^2=20(H-2.2)
putting it in the second equation
1/2 x m x 2.55^(20(H-2.2))=10mH
By solving we get H=2.6 (i hope this is the answer by the way which paper is this?:eek:)
 
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You have to apply completing square here :) this tough question
wow first completing the square question in mechanics :eek: i guess CIE r really changin the style of the questions !! i wonder whats gonna be new in tomorrow's paper..
 
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someone please draw the last graph!!7(ii) pleeeaseee
 

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wow first completing the square question in mechanics :eek: i guess CIE r really changin the style of the questions !! i wonder whats gonna be new in tomorrow's paper..
haha and the problem tht they award u only 2 to 3 marks :p
 
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how was it guys?........didn't do last part of the last question......but other than that mine went really well....btw in q6(the one in which gain if k.e was needed) was speed at top like 58 or 59 m/s...?
 
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how was it guys?........didn't do last part of the last question......but other than that mine went really well....btw in q6(the one in which gain if k.e was needed) was speed at top like 58 or 59 m/s...?
Speed at top was 20
 
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