A 50-kg box is being pushed along a horizontal surface. The coefficient of static friction between the box and the ground is 0.65, and the coefficient of kinetic friction is 0.35. What horizontal force must be exerted on the box for it to accelerate at 1.2 m/s2? A) 60 N B) 120 N Final formula: C) 170 N D) 230 N E) 490 N Required steps: 1) Draw free body diagram 2) Choose reference frame 3) Find vectors components 4 ) Apply Newton's 2nd law 5 ) Find the horizontal F algebraically 6) Check units 7 ) Substitute numerical values 6. A 15-kg block is on a frictionless ramp that is inclined at 20 above the horizontal. It is connected by a very light string over an ideal pulley at the top edge of the ramp to a hanging 19-kg block, as shown in the figure. The string pulls on the 15-kg block parallel to the surface of the ramp. Find the magnitude of the acceleration of the 19-kg block after the system is gently released? A) 4.0 m/s2 Final formula : B) 3.8 m/s2 15 C) 4.2 m/s2 D) 4.5 m/$2 Required steps: 1) Draw free body diagram 2 ) Choose reference frame 3) Find vectors components Apply Newton's 2nd law Solve for the acceleration. 6) Check units 7) Substitute numerical valuesNames 1. Three ropes are tied in a knot as shown in the figure. One student pulls on rope A with 1.0 N of force, and another student pulls on rope B with 7.0 N of force. How hard (magnitude) and in what direction must you pull on rope C to balance the first two pulls? Give the direction by specifying the angle (clockwise or counterclockwise) of the pull with the direction of rope A. Rope B Final formula: 120 Knot Rope A Rope C Required steps: 1) Choose axes 2) Find vectors components 3) Write the equation to balance the forces 4) Find the magnitude and direction of the force that pulls rope C 2. Two boxes are connected to each other by a string as shown in the figure. The 10-N box slides without friction on the horizontal table surface. The pulley is ideal and the string has negligible mass. What is true about the tension T in the string? ION A) T = 10 N B) T= 20 N C) T=30 N D) T 30 N 30 N Why