Kelli weighs 440 N, and she is sitting on a playground swing that hangs 0.41 m above the ground. Her mom pulls the swing back an

Question

3 years ago

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Kelli weighs 440 N, and she is sitting on a playground swing that hangs 0.41 m above the ground. Her mom pulls the swing back an

d releases it when the seat is 1.00 m above the ground. Assume that air resistance is negligible. If Kelli moves through the lowest point at 2.0 m/s, how much work was done on the swing by friction

Physics

1 answer:

kifflom [539] · Answer 1 · 2022-01-22T21:03:33+03:00

Answer:

Explanation:

Initial height from the ground = .41 m

Final height = 1m

Height by which Kelli was raised ( h )= .59 m

When she passes through the lowest point , she loses P E

= mgh

= 440 x .59

= 259.6 J

kinetic energy possessed by her

= 1/2 mv²

= .5 x (440/9.8) x 2²

= 89.8 J

Difference of energy is lost due to work by air friction

work done by friction = 89.8 - 259.6

= - 169.8 J