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Author Topic: Edexcel PHYSICS Doubts  (Read 137782 times)

Offline Igcseboy

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Re: Edexcel PHYSICS Doubts
« Reply #45 on: May 26, 2010, 06:44:03 pm »
Quote from: Austrakast on May 26, 2010, 06:38:07 pm

the normal reaction force should always be a normal to the/perpenicular to center of gravity

here r some stuffs on projectiles
http://www.astarmathsandphysics.com/a_level_physics_notes/forces_and_motion/a_level_physics_notes_equations_for_projectiles.html

if u still have problem with free body force diagram
take a look 2 this http://www.astarmathsandphysics.com/a_level_physics_notes/forces_and_motion/a_level_physics_notes_free_body_diagrams.html








thanxx

hey so wat do u expect of 2morrows paper is it gonna be easy like chemistry or ????
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Offline Darkstar3000

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Re: Edexcel PHYSICS Doubts
« Reply #46 on: May 26, 2010, 08:35:48 pm »
How are these supposed to be done

A particle is projected from level ground in such a way that its horizontal and vertical components of velocity are 20m/s and 10 m/s respectively. Find

a. the max height of the ball (i can do this)
b. its horizontal distance from the point of projection when it returns to the ground
c. the magnitude and direction of its velocity on landing
....................................

A pencil is accidentally knocked off the edge of a (horizontal) desk top. The height of the desk is 64.8 cm and the pencil hits the floor a horizontal distance of 32.4cm from the edge of the desk. What was the speed of the pencil as it left the desk?
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Offline T.Q

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Re: Edexcel PHYSICS Doubts
« Reply #47 on: May 26, 2010, 09:37:44 pm »
Quote from: Darkstar3000 on May 26, 2010, 08:35:48 pm
How are these supposed to be done

A particle is projected from level ground in such a way that its horizontal and vertical components of velocity are 20m/s and 10 m/s respectively. Find

a. the max height of the ball (i can do this)
b. its horizontal distance from the point of projection when it returns to the ground
c. the magnitude and direction of its velocity on landing
....................................

A pencil is accidentally knocked off the edge of a (horizontal) desk top. The height of the desk is 64.8 cm and the pencil hits the floor a horizontal distance of 32.4cm from the edge of the desk. What was the speed of the pencil as it left the desk?

a) V^2y=u^2y-2gs
    
    0=10^2-2(9.8)s
    
    s=5.1m

b) Vy=uy-gt
    
    0=10-9.8t
    
    t=1.02 for half the journey
    
    t=2x1.02=2.04s
    
    d=Vx(t)
    
    d=20(2.04)=40.8m

c) Vy=uy+gt
    
    Vy=10+9.8(2.04)
    
    Vy=29.992

    V=\sqrt{(29.992)^2+(20^2 ) }

    V=36

    tan\theta=\frac{29.992}{20}

    \theta=56.3
« Last Edit: May 26, 2010, 10:18:33 pm by T.Q »
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Offline T.Q

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Re: Edexcel PHYSICS Doubts
« Reply #48 on: May 26, 2010, 09:45:40 pm »
Quote from: Darkstar3000 on May 26, 2010, 08:35:48 pm


A pencil is accidentally knocked off the edge of a (horizontal) desk top. The height of the desk is 64.8 cm and the pencil hits the floor a horizontal distance of 32.4cm from the edge of the desk. What was the speed of the pencil as it left the desk?

uy=0

s=uyt+\frac{1}{2}gt^2

64.8=\frac{1}{2}gt^2

t=3.64s

V=\frac{d}{t}

V=\frac{32.4}{3.64}

V=8.9
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Offline Darth Austrakast

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Re: Edexcel PHYSICS Doubts
« Reply #49 on: May 27, 2010, 02:31:42 am »
Quote from: Igcseboy on May 26, 2010, 06:44:03 pm

thanxx

hey so wat do u expect of 2morrows paper is it gonna be easy like chemistry or ????

dude 1 thing i can tell u from my experience Physics is never easy  :P
but i found jan10 okay so i m afraid this may they might decide to change the pattern
just hoping no freaky questions!
Best of luck !
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Offline Darkstar3000

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Re: Edexcel PHYSICS Doubts
« Reply #50 on: May 27, 2010, 07:11:13 am »
Quote from: T.Q on May 26, 2010, 09:37:44 pm
a) V^2y=u^2y-2gs
    
    0=10^2-2(9.8)s
    
    s=5.1m

b) Vy=uy-gt
    
    0=10-9.8t
    
    t=1.02 for half the journey


    
    t=2x1.02=2.04s
    
    d=Vx(t)
    
    d=20(2.04)=40.8m

c) Vy=uy+gt
    
    Vy=10+9.8(2.04)
    
    Vy=29.992

    V=\sqrt{(29.992)^2+(20^2 ) }

    V=36

    tan\theta=\frac{29.992}{20}

    \theta=56.3

thank you
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Offline Igcseboy

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Re: Edexcel PHYSICS Doubts
« Reply #51 on: May 27, 2010, 10:55:46 am »
how was unit 1 paper????
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Offline Saladin

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Re: Edexcel PHYSICS Doubts
« Reply #52 on: May 27, 2010, 02:02:25 pm »
Quote from: Igcseboy on May 27, 2010, 10:55:46 am
how was unit 1 paper????

NO DISCUSSION UNTIL 24 HRS!
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Offline wakemeup

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Re: Edexcel PHYSICS Doubts
« Reply #53 on: May 28, 2010, 04:43:37 pm »
I'm assuming we can discuss the paper now.

Well, it started out pretty simple but became completely mind boggling towards the end, particularly that kite vector question. I understand it now but I messed it up in the exam so it doesn't matter. Plus, there were 20 questions. Most questions required quite a bit of thinking and I had much trouble handling the time.

Man, this is not good at all. I didn't well in the Physics practical and now this? It really sucks because I prepared pretty hard for this one. My only potential saving grace is paper 2 now and that is no walk in the park.
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Offline Saladin

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Re: Edexcel PHYSICS Doubts
« Reply #54 on: May 28, 2010, 05:34:27 pm »
Quote from: wakemeup on May 28, 2010, 04:43:37 pm
I'm assuming we can discuss the paper now.

Well, it started out pretty simple but became completely mind boggling towards the end, particularly that kite vector question. I understand it now but I messed it up in the exam so it doesn't matter. Plus, there were 20 questions. Most questions required quite a bit of thinking and I had much trouble handling the time.

Man, this is not good at all. I didn't well in the Physics practical and now this? It really sucks because I prepared pretty hard for this one. My only potential saving grace is paper 2 now and that is no walk in the park.

Yes for the kite thing you needed to use higher trig to answer it. But I got it in the end.
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Offline Igcseboy

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Re: Edexcel PHYSICS Doubts
« Reply #55 on: May 28, 2010, 06:57:17 pm »
Quote from: Engraved on May 28, 2010, 05:34:27 pm
Yes for the kite thing you needed to use higher trig to answer it. But I got it in the end.

wat was the tension and angle and all the questions tht followed????
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Offline wakemeup

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Re: Edexcel PHYSICS Doubts
« Reply #56 on: May 28, 2010, 07:25:02 pm »
Quote from: Igcseboy on May 28, 2010, 06:57:17 pm
wat was the tension and angle and all the questions tht followed????

I couldn't solve it myself during the exam but here's what you had to do. You had to resolve the Tension vector into horizontal and vertical components. Then, the vertical comp of T + weight = Upthrust and the horizontal comp of T = drag force. Now you can find the Tension and the angle.
« Last Edit: May 28, 2010, 07:57:19 pm by wakemeup »
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Offline T.Q

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Re: Edexcel PHYSICS Doubts
« Reply #57 on: May 28, 2010, 11:39:58 pm »
Quote from: Igcseboy on May 28, 2010, 06:57:17 pm
wat was the tension and angle and all the questions tht followed????

T=7.14
angel = 32
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Offline Saladin

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Re: Edexcel PHYSICS Doubts
« Reply #58 on: May 29, 2010, 07:06:03 am »
Quote from: T.Q on May 28, 2010, 11:39:58 pm
T=7.14
angel = 32

I got the same hi5!
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Offline Igcseboy

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Re: Edexcel PHYSICS Doubts
« Reply #59 on: May 29, 2010, 08:02:41 am »
Quote from: Engraved on May 29, 2010, 07:06:03 am
I got the same hi5!


i got the same :D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D

Alhamdulillah ... abit releifed
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