Physics: Post your doubts here!

[Minato112]

Can someone explain the answers to these questions?
The answers are q12)A
EDIT- q9 can be ignored as I found the answer.

Let the mass of these "things " be m.

You must use the principle of linear momentum here, i.e, Sum Of Linear Momentum Before = Sum Of Linear Momentum After

Sum Of Linear Momentum Before = Sum Of Linear Momentum After

(m x 60) + (m x -30) = (2m x v)

30 m = 2 mv

v = 15 m/s

Note: I used -30 since the velocity is in the opposite direction. As for the 2m, it's quite obvious. Since they stick together on impact, thier total mass is m + m = 2m

Hope It Helps.

 

[Yousif Mukkhtar]

Let the mass of these "things " be m.

You must use the principle of linear momentum here, i.e, Sum Of Linear Momentum Before = Sum Of Linear Momentum After

Sum Of Linear Momentum Before = Sum Of Linear Momentum After

(m x 60) + (m x -30) = (2m x v)

30 m = 2 mv

v = 15 m/s

Note: I used -30 since the velocity is in the opposite direction. As for the 2m, it's quite obvious. Since they stick together on impact, thier total mass is m + m = 2m

Hope It Helps.

Thanks, I used the kinetic energy method. I somehow got that wrong hahha. Can we use that method?

 

[Minato112]

Thanks, I used the kinetic energy method. I somehow got that wrong hahha. Can we use that method?

Im afraid no.

 

[Yousif Mukkhtar]

Im afraid no.

Thanks again. I guess these type of questions are really easy.

 

[Minato112]

Thanks again. I guess these type of questions are really easy.

No Problem. Indeed they are, well I mean there are more challenging questions

 

[Yousif Mukkhtar]

No Problem. Indeed they are, well I mean there are more challenging questions

Especially the ones with simultaneous equations.

 

[Minato112]

Especially the ones with simultaneous equations.

Yeah U can say but there are more tougher ones.

 

[floral123]

i have a question that why we say latent heat of fusion....why not fission....coz we going from solid to liquid...
though both the words should not be used here since nothing actually happens as such..i think...
any solutions friends...?

 

[floral123]

why increase in volume increases potential energy of substance?

 

[floral123]

what happens to potential energy of fluid when some of its molecules evaporate??
i think it should increase coz intermolecular forces become stronger since no of molecules are now decreased??
or we just say that pe is dependent on no of molecules so in this case issue of pe is invalid...?

 

[princesszahra]

Plz help me with Q.5 part (b) of this paper: http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_4.pdf
here is the ms : http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_ms_4.pdf

Just draw the arrangement! What else?

 

[SilverCrest]

can someone explain momentum to me?

 

[floral123]

can someone explain momentum to me?

momentum=product of mass and velocity.
law of conservation of momentum:
total initial momentum equals total final momentum in a isolated system in which bodies interact provided no external force is applied.
m1u1 +m2u2 = m1v1 + m2v2
this law is utilized in solving problems relating to collisions of objects...
types of collisions:
(Perfectly) elastic collision: Both momentum & kinetic energy of the system are conserved.
Inelastic collision: Only momentum is conserved, total kinetic energy is not conserved.
Perfectly inelastic collision: Only momentum is conserved, and the particles stick together after collision. (i.e. move with the same velocity.)

 

[Mystery]

Can Someone xplain how to solve this question??
9702/01/M/J/09 Q20
Answer : D

 

[aalmuhannadi]

This is an Edexcel question that I'm having trouble with. I'll write my answer and can someone please point out what's wrong with it (4 marks):
Newton's first law states than an object would continue with constant velocity or remain stationary if there;s no resultant force. When the train decelerates, there is a resultant force acting on each person in the direction that the train is travelling in. THis means that person A would fall and collide with person B as persons B and C would remain in their seats due to the fact that they have their backs on chairs which would absorb the force. Person A's motion is an example of a resultant force quoted in Newton's first law.

I'm pretty sure there's something wrong in there because not each point matches the mark scheme but that is how I would answer it, so does anyone know how they would go about correcting this?

 

[Trisha Graal Emile]

A car travels one complete lap around a circular track at a constant speed of 120 km/hr. Determine the magnitude of the displacement of the car in a time of 1.0 minute. (The circumference of a circle is 2πR where R is the radius of the circle.)

 

[Ding Ding]

A capacitor of capacitance C1 is charged to a p.d. of V0. The charging battery is then removed. A second capacitor of capacitance C2 is now joined to C1. (C2 is initially uncharged.)
(a) What is the final p.d. across the combination?
(b) If C2 is now disconnected, discharged and then connected to C1 again, and the process is repeated as before, what id the charge remaining after the tenth disconnection?
Please help me! I 'm really dunno how to answer this question . T_T

 

[Thampi4]

this question is physics A2 p4 O/N 08

hello
can someone pls explain me question
1aiii),b)
7ci),ii)


thanks in advance.

 

[saadatrezvi]

Physics 9702/M/J/09....MAY JUNE 09 paper 1 question# 15....can please anyone tell me that why the answer to this MCQ is option B? The new height after water flows from X to Y would be h/2
.

 

[Muhamad Y]

does potential increase because of resistance as more work has to be done on the charge