PHYSICS 1B Discussion Worksheet 1 Some Physics 1A review Problem 1 Three people try to pull a car that is stuck in mud The three forces they apply are shown in the gure below a Find the net force applied to the car by the people Write your answer as a vector using unit vectors b Find the magnitude and angle measured counterclockwise from the x axis of this net force E 179 38N aboi 847 4j L of magefrettify Fy 847 35N I ta E E F cosfx F Sinty FeF Farndx Encety i FsLo tx Fysinty I I magnitude 866 ION A 780 ekg Problem 2 A particle with mass m 9 g moves along the x axis subject to a single conservative force with potential energy function U x Ax2 Bx3 where A 2 0 J m2 and B 0 3 J m3 The particle is released from rest at x 1 0 m a What is the particle s speed at x 4 0 m b What is the particle s acceleration at x 4 0 m dx E k V x DE k U x 0 U xo Eo U xoS Ez kx u x dx F v VotTadt ke Ukd UkeU x fmadx k Emv u x m adx Uv I u x mv ng y mgY r he a x u x xav 1 Yt 6 a 0 177 1 o xx