Question

330 As shown in the figure, a 25 kg block is being pulled by a force Fup along a rough incline. The coefficient of kinetic friction between the block and the incline is uk = 0.30. Keep 2 decimal places in all answers. Step 1: Start by drawing a free body diagram of the block, including all the forces exerted on the block. Label the normal force as FN, label the weight as weight. Since the type of the frictional force is kinetic, represent it by vector fk You should be able to calculate the weight of the block. But the Force F and the normal force FN, and kinetic friction fk are unknown. For each force, write its x component and y component. (Use F and Fn as "space holder for the unknowns). You can write fk from its formula. Pay attention to the geometry and trigonometrical functions. Step 2: Apply NEwton's second law Apply Fy = may, what should ay be equal to?, obtain first equation. (a) Solve for the magnitude (in Newtons) of the normal force FN, it is: Enter a number N Submit (5 attempts remaining) (b) What is the magnitude (in Newtons) of the kinetic frictional force? Enter a number N Submit (5 attempts remaining) Apply Fx = max, to this problem, obtain the second equation. If the block is moving at constant velocity, what is az? no submission needed (c) What is the magnitude (in Newtons) of force F in order to keep the block moving up the incline at a constant velocity? Enter a number N Submit (5 attempts remaining) (d) If force F is reduced to 94 N, Apply Fx = max, what is the acceleration (in m/s2) of the block? Pay attention to the sign.

Answer 1

Fr P.B.D 9-33 (Eoro blanes clog yariy) (9) 25 x 9.8 x coi 33 N Hamune N 205.47 N fN MR (b) Eriction Eoree 1 20 5.47 7 antres NO 6/-64 - 1 (G) Im ardr to mone auith camitanmt velac k tanme f (P