A contestant in a winter games event pushes a 46.0 bg block of ice across a frozen lake as shown in Figure 4.29[a). The coefficient of static friction is 0.1 and the coefficient of kinetic friction is 0.03. Fpush Finsh TN Epushing Fpush x = Fpush Cos / 25 Fpushy = Fpush SIn / 25" Farav = mq Figure 4.29 Dote that normal force events extra force because (a) Calculate the minimum force F he must exert to get the block moving. IN supports against both (b) What is its acceleration once it starts to move, if that force is maintained? gravity + pushing downward m/'s a ) y- forces: Fgray - N+ Fpushy = O ( no net force vertically ) 3) N = Formint Fpushy = 450.8 + Fpush Sin 25 X -forces: Fpushx - Friction = O ( until gets rock moving.) 2 Tpush Cos 25 - M, N=0 * case stactic JAs 2 Foush Cos 25 - (0 . 1 ) ( 45 0. 8 + Fpush sin 25 ) = 0 b ) only need to deal with horizontal motion I kinetic friction here Fpush - Ffriction = ma ( 52. 2 cobb)- (0.03 ) N = (46.0 kg ) a Solve for N: 52. 2.02 (0,03 ) ( 473 ) = (46)(a) N= 450.8 + Fpush Sin 25 = 450.8 + (52.2) (sin 25 = 473 Newtons