Physics: Post your doubts here!

[Xtreamer]

– Ans: C. gravitational PE = 1 + (0.2x0.3) = 1.06J

Source: http://physics-ref.blogspot.com/2014/10/9702-june-2014-paper-12-worked.html

 

[Abdul Hanan]

how?

 

[Aly Emran]

Guys how to do these type of qstns? Plzz explain
Thanks in advance

 

[princess Anu]

No

What is the Answer is it D?

A

 

[Ahmed Aqdam]

View attachment 54947
how?

F=qE so E=F/q
Now according to work done formula F=K/d.
Hence K/dq.

 

[princess Anu]

Yes but it is like this. Rise = Final - 40.
Why is 40 counted in this?

Counted in what?

There could be a change in mass.

so? :S

 

[Xtreamer]

No

A

Then i think the explanation wud b that at the centre of object the weight or resultant force acts cuz its its most balanced there......lol

 

[Ahmed Aqdam]

Counted in what?


so? :S

The momentum is constant so if the mass changes there would be a change in the velocity but momentum would be constant with zero resultant force.

 

[Abdul Hanan]

F=qE so E=F/q
Now according to work done formula F=K/d.
Hence K/dq.

can you explain a bit more please? i'm sorry but i don't get it.

 

[Ahmed Aqdam]

can you explain a bit more please? i'm sorry but i don't get it.

The force on the charge is equal to qE (E is electric field strength).
Now work done= Fd
Work done here is in the form of kinetic energy so K=Fd and F=K/d.
Insert this value of F in the equation F=qE.

 

[Xtreamer]

can you explain a bit more please? i'm sorry but i don't get it.

See this
http://www.physchem.co.za/OB11-ele/charge3.htm

 

[Abdul Hanan]

The force on the charge is equal to qE (E is electric field strength).
Now work done= Fd
Work done here is in the form of kinetic energy so K=Fd and F=K/d.
Insert this value of F in the equation F=qE.

See this
http://www.physchem.co.za/OB11-ele/charge3.htm

Thanks a lot !

 

[Abdul Hanan]

 

[Xtreamer]

Guys which year is more important 2009 or 2013????

 

[Abdul Hanan]

Guys which year is more important 2009 or 2013????

2009.
but if you haven't tried p11 2012 try that its a must do paper.

 

[asadalam]

View attachment 54950

Momentum = mv
We need to find the velocities at the 2 instants mentioned.
As the golf ball reaches the surfaces after being dropped, all its potential energy is converted to kinetic energy.
½ mv12 = mgh1
Speed v1 as the ball reached the surface = √(2gh1)
Similarly, the kinetic energy of the ball just as it leaves the surface is converted to potential energy at height h2.
½ mv22 = mgh2
Speed v2 just as the ball leaves the surface = √(2gh2)
The direction of motion of the golf ball changes after hitting the hard surface, so the initial momentum should be added.
Total change in momentum = m (v2+v1)
Total change in momentum = m√(2gh1) + m√(2gh2)

2009.
but if you haven't tried p11 2012 try that its a must do paper.

Summer or winter?

 

[Abdul Hanan]

Momentum = mv
We need to find the velocities at the 2 instants mentioned.
As the golf ball reaches the surfaces after being dropped, all its potential energy is converted to kinetic energy.
½ mv12 = mgh1
Speed v1 as the ball reached the surface = √(2gh1)
Similarly, the kinetic energy of the ball just as it leaves the surface is converted to potential energy at height h2.
½ mv22 = mgh2
Speed v2 just as the ball leaves the surface = √(2gh2)
The direction of motion of the golf ball changes after hitting the hard surface, so the initial momentum should be added.
Total change in momentum = m (v2+v1)
Total change in momentum = m√(2gh1) + m√(2gh2)

Summer or winter?

Sorry didn't mention that its winter.
And thanks for the explanation.

 

[Xtreamer]

View attachment 54950

this question is from which year and paper???

 

[Abdul Hanan]

this question is from which year and paper???

don't know. A friend of mine sent it to me with the answer. Now he's asleep.

 

[Ahmed Aqdam]

don't know. A friend of mine sent it to me with the answer. Now he's asleep.

Any idea why aluminium can sustain more plastic deformation than steel?