Question

. A boy pulls a sled of mass m-10.0 kg which slides at constant speed on a ground with kinetic friction coefficient u-0.500. The sled is tied to a rope, and he pulls the rope at an angle of 30.0 with respect to the horizontal axis a. Draw a sketch of this problem b. Draw the free body diagram for the forces acting on the sled, including the coordinate system used to solve the problem. Do not draw the free body diagram on top of the sketch. Write down the components of Newton's second law for the sled. DO NOT PLUG IN NU M131 Rs. What is the tension in the rope? c. d. With how much force would he have to pull the rope at the same angle to make the sled lift off the ground? e. [Answers: (a) Draw! (b) Draw! (c) Write! (d) 43.9 N (e) 196 N]

Answers are given. You just have to show how to reach those answers clearly.

Answer 1

(a) Sketching a problem (b) Free body diagram (c) Horizontal components H_x = T cos theta - F_Fric = ma (i) vertical components V_y = R + T sin theta = mg (ii) \r\n (d) T = -- ? F_Fric = mu_k R = 0.500 times R since velocity is constant hence, a = 0 m/s^2 so, From equation (i) T cos theta - F_Fric = ma T cos theta - 0.5R = 0 times m = 0T cos 30 degree - 0.5 R = 0 rightdoublearrow 0.866 T - 0.5 R = 0 (iii) from equation (ii) R + T sin theta = mg R + T sin 30 degree = 10 times 9.8 rightdoublearrow R + 0.5 t = (iv) \r\n solving equation (iii) and equation (iv) we get, T = 43.906 N and R = 76.04 N Tension T = 43.9 N