physics cie ques

[Sue T]

from mj09 ppr1 i need help with :
Q) 13,15,18 , 20
please!

 

[PlanetMaster]

May/June 2009 Paper 01:
MCQ 13:
900N x 0.2m = (F x 0.6m) + (F x 0.6m)
180 = 1.2F
F = 150N

MCQ 15:
After tap is opened, water in Y has height h/2 and mass m/2.
So potential energy lost from X = Potential energy gained in Y
= (m/2) x g x (h/2)
= (mgh)/4


MCQ 18:
Change in height = h+h
Increase in pressure = (h+h)ρg
Increase in pressure = 2hρg

 

[lee91]

planet master, for mcq qs 18, why do we need to add up the rise on the right, and drop on the left? please help.

also would you mind in explaining p11/0N 09 MCQ 13 and 14? thank you in advance

 

[Sue T]

thank u
n pls question 20 as well (same ppr)

 

[intel1993]

elasticity means that when load is removed then the object reagian its orignal shape....
n palstic behaviour mean that at some instant the oobject gains permanant deformation .........................

due to which ans is D.....................

 

[PlanetMaster]

planet master, for mcq qs 18, why do we need to add up the rise on the right, and drop on the left? please help.

We've added both.
The rise in height was h and the drop in height on the left was also h.
So that makes up 2h.

also would you mind in explaining p11/0N 09 MCQ 13 and 14? thank you in advance

Oct/Nov 09 Paper 11
MCQ 13:
Radius of Q = 0.05m
Torque = Radius x Force
Force = Torque / Radius
Force = 3/0.05
Force = 60N
Force applied will be the tension in top of belt as there is no other opposing force.
Torque on P = Radius x Force
Torque on P = (75/1000) x 60N
Torque on P = 4.5Nm

MCQ 14:
Since angle is 45°, horizontal & vertical velocity components are equal.
At highest point, vertical velocity component is 0 so kinetic energy of the particle is 0.5 of original that is 0.5E

 

[PlanetMaster]

thank u
n pls question 20 as well (same ppr)

Stress of P = TP/A
Stress of Q = 2TQ/A
Strain of P = e/l
Strain of Q = e/2l

Since their Young Modulus is equal, therefore:
TP/A = 2TQ/A
.e/l......e/2l
TP = 4
TQ

 

[lee91]

planet master, i'm sorry i still dont understand why do you have to add it up. what is the reason behind, could you pretty please explain?

and for mcq 14, since the vertical velocity is zero, then according to 1/2mv^2, i thought the kinetic should be zero? how to relate them??

thank you.

 

[joelynn]

can anyone pls help me to solve question 16 june paper 2005?? urgent pls!!
thx a lot!