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(2)Compute the x and y coordinates of the centre of mass of the piece.

=> i'm not sure what steps are to computing coordinates. I have a cartesian plane with a block shaped 'C'... Do i just break it down into geometric shapes (i.e. rectangles/squares) and compute the CM of each one, then what do i do to get the CM of the total block?

(3) A 40 kg box initally at rest is pushed 5.00m along a rough, horizontal floor

with a constant, applied horizontal force of 130 N. If the coefficient of

friction between box and floor is 0.300, find:

(a) the work done by the applied force

(b) increase in internal energy in the box-floor system due to friction

=> I know w=u*Fn*d to find work due to friction, how do i go by finding the INCREASE in internal energy?... kinetic energy = 1/2mv^2?

(c) the work done by normal force

(d) the work done by gravitational force

=> for Wg=mgdcos(theta)... is thetha perpendicular (90 degrees) to horizontal?

(e) the change in kinetic energy of the box

=>change in kinetic energy of box, equals Ek after - Ek before... how can i solve for this if i dont know the final velocity?

(f) the final speed of the box

=> conservation of kinetic energy is used?

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# Homework Help: Physics - kinetic energy

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