Answer:
a) 633.39 J
b) 0.28
Explanation:
a)The kinetic energy of the player = 
Work done by friction = energy change of the player
= 
= 633.9 J
b) Assuming the frictional force stays constant,
Work done by friction = Frictional force×distance
Frictional force = kinetic friction(μ)×normal reaction
Normal reaction = weight = mass×gravitational acceleration ( g=10m/s2 )
Combining these equations
633.9 = F×3.4 ⇒ F = 186.44 N
F = μmg ⇒ μ = F/mg
= 186.44/670
= 0.28
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Answer:
7.9 x 10^21 pound-force
Explanation:
The average distance between the Earth and sun is 150 trillion meters, or 1.5 x 10^11 meters. The mass of the sun is 1.99 x 10^30 kilograms, while the Earth weighs in at 6.0 x 10^24 kilograms. The gravitational constant is 6.67 x 10^-11 meter^3 / (kilogram - second^2). So the Earth and sun pull on each other with a force equal to 3.52 x 10^22 newtons. The newton is a unit of force equal to a kilogram-meter/second^2. One newton is equal to 0.22 of the rarely used English unit called pound-force, so 3.52 x 10^22 newtons is 7.9 x 10^21 pound-force.
