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Biology; Chemistry; Physics: Post your doubts here!

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Question for you guys, designed by myself :D
A bicycle moves round a turn with a constant speed. What two statements from the following explain the force acting on the bicycle and its direction of acceleration?
1 Since the speed is constant, there is no force acting on the cycle.
2 Since the speed is constant, there is no acceleration.
3 A force acts on the cycle towards the center of the round turn.
4 Acceleration acts towards the center of the round turn.
5 Acceleration and force both act perpendicularly to each other with acceleration being tangent to the round turn and force towards the center.

A) 1 and 2
B) 3 and 5
C) 2 and 3
D) 3 and 4

My guess is that the answer should be D.
3 because in circular motion there is always a force acting towards the center i.e the centripetal force.
4 because in circular motion the displacement is constantly changing i.e there is no fixed direction, so according to velocity = displacement/time taken, the velocity is also changing, hence further according to acceleration = change in velocity/time taken, there is also an acceleration acting. So constant change in displacement = constant change in velocity = constant acting of an acceleration.
Hope I'm right? :p either way, nice question :)
 
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umm yeah m
i just thought over it and it turns out it is actually D
look the wheel is pushing the car towards the left side ( the one to which acceleration is being made) so just think when the tyre moves the tyre pushes towards the left side with the help of friction
i dont think you can understand this..:/
What do you mean i can't understand ...... Or you mean you can't explain cuz you even don't know ur self..
 
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This is an interesting one :) the answer is D. They are asking in which direction is the frictional force acting on the WHEEL, not the car. If it was the car, then the answer would be B. Picture this, if the car is moving towards the left, then obviously the wheels will move in an anticlockwise motion to move the car, no? If the wheels move in an anticlockwise motion, they rub against the road surface in a direction acting towards the right. So a car moving leftwards = wheels rubbing against the road surface rightwards.
Now what is the purpose of friction? To provide hindrance on a resultant acting force. How does it do that? By acting in the opposite direction of the resultant force. In this case the acting force of the wheel against the road surface is rightwards, so the direction of the frictional force will act opposite to it i.e leftwards, hence option D is correct. Hope this clears your concept to some extent :)
 
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what will be volume of a gas if pressure on it is released from 22mm-Hg to 12 mm-Hg ????
i think there's something missing in ur question o_O pplz check it again. bcuz we need to have at least one value for volume to calculate the other one.
 
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i told him, not showed him :p

anyway, just posting some difficult MCQs, if someone could please explain:
s09 Q30
http://www.xtremepapers.com/papers/...onal O Level/Physics (5054)/5054_s09_qp_1.pdf
w09 Q29
http://www.xtremepapers.com/papers/...onal O Level/Physics (5054)/5054_w09_qp_1.pdf
w10 Q29
http://www.xtremepapers.com/papers/...nal O Level/Physics (5054)/5054_w10_qp_11.pdf

and could also post other difficulties i encounter as well if u guys want, as some MCQs might be easy for some but help others, so let me know!
U did this mcq paper w09 paper 1 can u help me with mcq no 22 !
 
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