Hey today I got back the paper I did in January so unfortunately I don't have a mark scheme yet. But these are 3 questions I got wrong, can someone PLEASE help me figure out how to do them?
Thank you so much for any help
Questions 4 and 5 are driving me absolutely nuts.
Sorry for my diagram scribbles!
-Question 4http://www.flickr.com/photos/51956290@N0…
-Question 5 (They both refer to diagram in question 4) http://www.flickr.com/photos/51956290@N0…
-Question 10 http://www.flickr.com/photos/51956290@N0…
Thank you so much for any help
Questions 4 and 5 are driving me absolutely nuts.
Sorry for my diagram scribbles!
-Question 4http://www.flickr.com/photos/51956290@N0…
-Question 5 (They both refer to diagram in question 4) http://www.flickr.com/photos/51956290@N0…
-Question 10 http://www.flickr.com/photos/51956290@N0…
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Well, question 4 asked for the component of R parallel to the plane. R is the reaction of the component of W at right angles to the plane. It has no component parallel to the plane. What you gave was the component of W parallel to the plane which IS WsinѲ. So answer A is correct.
For question 5, since you are given no information about the coefficient of static friction, we have to assume that the plane is frictionless. So the block will accelerate down the plane so answer C is correct.
For question 10, this is a badly written question. The diagrams show that the lift goes up to the floor above and then back down again. This is what I THINK it means when it asks for the acceleration against time for the WHOLE journey. Whoever wrote the question was trying to be clever and failed miserably!!
Since the lift is going up, it will accelerate, then move at constant speed, i.e zero acceleration, then decelerate and come to a stop. It then returns to the floor below. Upward acceleration is positive so deceleration is negative, so answer B look right to me.
For question 5, since you are given no information about the coefficient of static friction, we have to assume that the plane is frictionless. So the block will accelerate down the plane so answer C is correct.
For question 10, this is a badly written question. The diagrams show that the lift goes up to the floor above and then back down again. This is what I THINK it means when it asks for the acceleration against time for the WHOLE journey. Whoever wrote the question was trying to be clever and failed miserably!!
Since the lift is going up, it will accelerate, then move at constant speed, i.e zero acceleration, then decelerate and come to a stop. It then returns to the floor below. Upward acceleration is positive so deceleration is negative, so answer B look right to me.