Forces (Week 2)

Sunday, 11 March 2018

10:41 PM

Machine generated alternative text:
Feedback for Part 1) 
You have correctly entered the first component. 
You have correctly entered the second component. 
You have correctly entered the third component. 
Marks for this submission: 0.33/0.33. Accounting for previous tries, this gives 
0.00/0.33. 
Feedback for Part 2) 
You have correctly entered the first component. 
You have correctly entered the second component. 
You have correctly entered the third component. 
Marks for this submission: 0.33/0.33. Accounting for previous tries, this gives 
0.00/0.33. 
Feedback for Part 3) 
You have calculated the normal force. This is perpendicular to the 
surface of the track (Figure 3), so: 
Horizontal component 
tan(9) — 
Vertical component 
from which you can solve for 9. 
(mv2 / R) 
mg 
k 
-i 
Figure 3: Diagrammatic representation of the horizontal and vertical 
force components of the normal force. The normal force vector is 
perpendicular to the track and points diagonally upwarde,. The 
horizontal component points in the direction of —i and the vertical 
component points vertically upwards in the direction of —k. 
Marks for this submission: 0.00/0.33. This submission attracted a penalty of 
0.11.

 

Machine generated alternative text:
Your answer is partially correct. Note: Your answers should be correct to 3 significant figures. 
Feedback for Part 1) 
You have correctly entered the first component. 
You have correctly entered the second component. 
You have correctly entered the third component. 
Marks for this submission: 0.33/0.33. Accounting for previous tries, this gives 0.00/0.33. 
Feedback for Part 2) 
You have incorrectly entered the first component. 
You have incorrectly entered the second component. 
You have incorrectly entered the third component. 
Newton's second law tells us that the resultant force, 
is equal to the sum of the forces 
acting on the car (Figure 2). In this situation the weight force, —mgk and normal force N are 
acting on the car: 
You should evaluate this. 
mv2 
mg 
mg 
mv2 
Figure 2: A free body diagram of the forces acting on the car. The centripetal force vector is 
pointing horizontally towards the centre of rotation around the track. The weight force is pointing 
straight down, whereas the normal force is perpendicular to the track and is pointing diagonally 
upwards. The angle made between the weight force and the normal force when the three vectors 
are joined together is equal to the angle at which the track is banked, i.e. 0.

 

 

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