I am repeating my As level.

Thought blocker

Thought blocker

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dumb human said:
Thought blocker MAN PLZ EXPLAIN QUESTION 9.. OCT/NOV/PHYSICS
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w09_qp_12.pdf
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dumb human said:
A

And Q)13 Too :/
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9)
force=rate of change of momentum
60=-(30v-30*3)/0.5 (i put a minus sign before the bracket because the force is a retarding force, so the acceleration will be negative)
v= 2

13)
assuming it is projected with velocity v, so the initial KE, E= (mv^2)/2
at the highest point, the vertical component of the veolcity = 0, so its left with v cos 45,
so final KE = 1/2 x m x (v cos 45)^2 = 0.5E
 
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Thought blocker said:
9)
force=rate of change of momentum
60=-(30v-30*3)/0.5 (i put a minus sign before the bracket because the force is a retarding force, so the acceleration will be negative)
v= 2

13)
assuming it is projected with velocity v, so the initial KE, E= (mv^2)/2
at the highest point, the vertical component of the veolcity = 0, so its left with v cos 45,
so final KE = 1/2 x m x (v cos 45)^2 = 0.5E
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i did 9th one the same way...but i get 4..... :/
and i tried 13th one your way.....but i get 0.71 :(
 
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dumb human said:
i dont knw question 14 and 15 also ......
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14)
By conservation of momentum, 2 x 2 = 1 x v, v =4
so the 1kg trolley moves 4ms-1 to the right,
calculating the total KE of the both trolleys, which is 1/2 x 2 x 2^2 + 1/2 x 1 x 4^2 = 12J
assuming no energy is lost, the energy stored in the spring is converted to KE gained by the trolleys, so its 12J

15)
Show me your workings... its easy.
 
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God you guys are confsed over uncertainites like this in As what will happen in A2s when the whole world of uncertainities will change :p

Thought blocker said:
14)
By conservation of momentum, 2 x 2 = 1 x v, v =4
so the 1kg trolley moves 4ms-1 to the right,
calculating the total KE of the both trolleys, which is 1/2 x 2 x 2^2 + 1/2 x 1 x 4^2 = 12J
assuming no energy is lost, the energy stored in the spring is converted to KE gained by the trolleys, so its 12J

15)
Show me your workings... its easy.
Click to expand...
ur questions are answered by now i guess?
 
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Thought blocker said:
14)
By conservation of momentum, 2 x 2 = 1 x v, v =4
so the 1kg trolley moves 4ms-1 to the right,
calculating the total KE of the both trolleys, which is 1/2 x 2 x 2^2 + 1/2 x 1 x 4^2 = 12J
assuming no energy is lost, the energy stored in the spring is converted to KE gained by the trolleys, so its 12J

15)
Show me your workings... its easy.
Click to expand...


i got 14 now...but i dont knw how to do 15.. should i do, I=P/V ?
 
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