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Forces Homework. Fg = m*g – simplest calculation for objects near the surface of the Earth Fg = G m 1 m 2 - for any two objects d 2 - G = 6.67x10 -11 Proportions Fg α 1/d 2 - if d increases, Fg decreases - if d decreases, Fg increases Fg = Fg i * 1/d 2. 1. Fg = m*g
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Forces Homework Fg = m*g – simplest calculation for objects near the surface of the Earth Fg = G m1m2- for any two objects d2 - G = 6.67x10-11 Proportions Fg α 1/d2 - if d increases, Fg decreases - if d decreases, Fg increases Fg = Fgi * 1/d2
1. Fg = m*g Fg = 4.5 kg*9.8 N/kg = Newtons 2. Fg = m*g 167 N = m*9.8 N/kg m = 167N/9.8 N/kg m = kg 3. Fg = m*g 408 N = 250 kg * “g” g = 408N/250 kg g = N/kg or m/s2 P 93
Fg1 = d22 Fg2d12 700 N = 102 x 12 Fg = N 2. a. Fg = m*g = 1x105 kg * 9.8 N/kg = N b. 128000 = 20 x as far as in 6400 part a Fg1 = d22 Fg2d12 Fg = N 30 times as far (1/302) Really far (9x1011 times as far away) 1/d2 = ?? P. 96
3. Fg1 = d22 Fg2d12 50000N = (1/4)2 x 1 = 50000 /(1/16) = 50000 * 16 = N 4. Fg1 = d22 Fg2d12 How has d changed? Initial: di = 6400 km Now: df = 6600 km So df/di = 6600/6400 = x larger Fg2 = 9.8 N/kg * 1/1.032 = 9.8 * 1/1.06 = N/kg P 96
Fg = G m1m2 d2 = 6.67x10-11(60)(70) 12 = N 2. Fg = G m1m2 d2 =6.67x10-11(2000)(2000) 2.52 = N P 98
a. ME = 6x1024 kg Fg = G m1m2 d2 = 6.67x10-11(6x1024)(1) (20,000,000m)2 = N b. 20,000 / 6400 = 3.13 times the radius of Earth Fg = Fgi * 1/d2 = 9.8N * 1/(3.13)2 = 9.8N * 1/9.797 = N P 98 # 3 – two solutions