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A 40 kg box initially at rest is pushed 5 m along a rough, horizontal floor with a constant applied horizontal?
A 40 kg box initially at rest is pushed 5 m along a rough, horizontal floor with a constant applied horizontal force, the work done by the applied force is 650 J. If the final speed of the box is 1 m/s, find the work done by friction.
2 Answers
- Anonymous9 years agoFavorite Answer
force done on the box by applied force = 650/5 = 130 N
total force on box = 130 - F (where F is the force of friction)
acceleration on box = (130-F)/40 = (3.25 - F/40)m/s²
v² = u² +2as
1 = 0 + 2(3.25 - F/40)(5)
1 = 32.5 - 0.25F
0.25F = 31.5
F = 31.5/0.25 = 126 N
work done by friction = -126*5 = -630J
- PearlsawmeLv 79 years ago
Work done by the applied force is 650J
Kinetic energy gained by the box = 0.5*40*1*1 =20 J
Work lost due to friction= 650 - 20 = 630 J
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