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A block of mass 3.73 kg is pushed 2.68m along a frictionless horizontal table by a...

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w63258741 | Student, Undergraduate | eNotes Newbie

Posted October 23, 2011 at 1:55 PM via web

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A block of mass 3.73 kg is pushed 2.68m along a frictionless horizontal table by a constant 16 N force directed 24 degree below the horizontal.

Find the work done by the applied force, work done by the normal force exerted by the table, work done by the force of gravity and the work done by the net force on the block.

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted October 23, 2011 at 10:13 PM (Answer #2)

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Force is a vector that has both a magnitude and a direction. Similarly, displacement is also a vector. Work is the dot product or scalar product of the vectors representing force and displacement. It is given by W = F*d*cos x, where x is the angle between the force vector and displacement vector.

Here, the force of 16 N makes an angle of 24 degrees with the horizontal. The displacement due to the force is a 2.68 m in the horizontal direction. The work done by the applied force is 16*2.68*cos 24 = 39.17 J

The normal force does no work as cos 90 = 0

Similarly the gravitational force does no work.

The work done by the net force is 39.17 J

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