WEEK 3 physics 151 - Webassign Solutions PDF

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Webassign Questions Assignment 7, Problem 7

GIVENS mass of boat = 3400 Kg initial position = m final position = m Jack’s force = N Jill’s force = N UNKNOWNS work done by Jack = ? J work done by Jill = ? J person who exerted a force perpendicular to the displacement of the boat = ? final speed of boat = ? m/s EQUATIONS WORK:

DISPLACEMENT:

CONSERVATION OF ENERGY:

WORK Δr = rf - ri Δr = - Δr = m W = F * Δr Wjack = * Wjack = Wjack = -840 + 0 -210 Wjack = -1050 J W = F * Δr Wjill = * Wjill = Wjill = 300 + 0 - 300 Wjill = 0J Jill exerted a force perpendicular to the displacement of the boat ΔW = ½ * m (vf - vi)2 -1050 = ½ m (vf - vi)2 Vf2 = ( (-1050 * 2) / m ) + vi 2 Vf2 = ( -2100 / 3400 ) + (1.1)2 Vf = √( -2100 / 3400 ) + (1.1)2 Vf = 0.77 m/s SOLUTION

Assignment 7, Problem 8

GIVENS spring constant (K) = 20 N/m equilibrium length (L1 ) = 0.1 m stretched length (L2) = 0.2 m UNKNOWN work done = ? J EQUATIONS E = ½ k * x2 x = L2 - L1 WORK x = 0.2 m - 0.1 m x = 0.1 m E = ½ * 20 N/m * (0.1 m)2 E = 0.1 J SOLUTION...