Physics: Post your doubts here!

[lisahamed]

A building has 5 floors. The windows on successive floors are separated by the same
vertical distance. A brick is dropped from a window on each floor at the same time.
The bricks should hit the ground at
A decreasing time intervals
B equal time intervals
C increasing time intervals
D the same time
Why is the answer A?

 

[Tabi Sheikh]

A building has 5 floors. The windows on successive floors are separated by the same
vertical distance. A brick is dropped from a window on each floor at the same time.
The bricks should hit the ground at
A decreasing time intervals
B equal time intervals
C increasing time intervals
D the same time
Why is the answer A?

Because as the distance increase from the ground there is more time for gravitational acceleration to act upon bricks hence increasing their speeds more and more that's why the time interval will be decreasing.

 

[Tabi Sheikh]

Please help me with the question below.. I don't understand how to solve vector questions!

A ship is pulled at a constant speed by two boats A and B, as shown in the diagram. The engine of the ship does not produce any force.

The tension in each cable between A and B and the ship is 4000N.

(i) Draw a free body diagram showing the three horizontal forces acting on the ship.
(ii) Draw a vector diagram to scale showing these three forces and use your diagram to find the value of the drag force on the ship.

Could anyone please spare some time and draw the needful diagrams?
Thanks

ans to your part one is in the diagram hope the second one will be easier for you after this

 

[salvatore]

ans to your part one is in the diagram hope the second one will be easier for you after this

Thanks a lot for your help.. I figured this out before.
Part (ii) of the question is bothering me..

 

[Tabi Sheikh]

whats with part (ii)?

 

[salvatore]

whats with part (ii)?

(ii) Draw a vector diagram to scale showing these three forces and use your diagram to find the value of the drag force on the ship.

 

[Tabi Sheikh]

(ii) Draw a vector diagram to scale showing these three forces and use your diagram to find the value of the drag force on the ship.

do you have any values for forces?

 

[salvatore]

do you have any values for forces?

Yeah.. as it is said in the question:
The tension in each cable between A and B and the ship is 4000N.

 

[Tabi Sheikh]

You can decompose the two forces in components add the resultants in x direction and it will be equal to frictional force since the speed is constant......
hope u can understand the logic
i'm a bit busy now InshAllah I will upload the diagram of it ASAP.....

 

[salvatore]

You can decompose the two forces in components add the resultants in x direction and it will be equal to frictional force since the speed is constant......
hope u can understand the logic
i'm a bit busy now InshAllah I will upload the diagram of it ASAP.....

I get your point partially.. will be waiting for the diagram.
Thanks!

 

[Jspake]

A skier of mass 75 kg accelerates from rest down the slope as shown in the diagram. At the bottom of the slope, he is travelling at 40 m/s.
What is the average force opposing his motion down the slope?

Please help me solve the question..
Thanks

 

[Tabi Sheikh]

I get your point partially.. will be waiting for the diagram.
Thanks!

hope this will help you.

 

[Tabi Sheikh]

A skier of mass 75 kg accelerates from rest down the slope as shown in the diagram. At the bottom of the slope, he is travelling at 40 m/s.
What is the average force opposing his motion down the slope?

Please help me solve the question..
Thanks

I think there is some information missing about the question can you please post the link of the past paper also post the question numbers........

 

[A*(a*)]

Anyone with Physics specimen of paper2 or paper1?

 

[A*(a*)]

duhhh! i know but its final minus initial so the answer choice b and d are weird . A and c are wrong cuz they don't consider change in time. p2 is negative so the answer should be minus p2 minus p1 over change in time.... Can u answer my other mcqs as well

Anyone with Physics specimen of paper2 or paper1?

 

[Bloodlines]

that skier one question..
firstly calculate G.P.E....at the top, which the skier possess...by the relation E.P=mgh=750*300...
now calculate K.E at the bottom....K.e=0.5*75*40^2

 

[Bloodlines]

calculte the difference of energy....
this energy would be lost due to the frictional efeects....now calcate the force by Workdone=force*d

 

[Tabi Sheikh]

calculte the difference of energy....
this energy would be lost due to the frictional efeects....now calcate the force by Workdone=force*d

never thought about it that way...... good work..........

 

[Jspake]

that skier one question..
firstly calculate G.P.E....at the top, which the skier possess...by the relation E.P=mgh=750*300...
now calculate K.E at the bottom....K.e=0.5*75*40^2

calculte the difference of energy....
this energy would be lost due to the frictional efeects....now calcate the force by Workdone=force*d

Thanks man

 

[aleezay]

Please share the link for the examiner report for November 2011's paper if any one has it asap. Thanks in advance