Question

Level II: Newton's Law. A mass m box can either be pushed or pulled over sand at the beach. Draw separate free- body diagrams on the box for the push and pull cases (assume the magnitude of the push and pull forces are the same). The coefficient of kinetic friction between the box and sand is thk. Derive an algebraic acceleration equation for the push and for the pull cases. Derive the velocity vs. time equation, and derive the position vs. time equation for the two cases. Draw the acceleration vs. time graph, and the velocity vs. time graph for the two cases. Assess which case, the push or pull is the most efficient way to move the person on the sled? Explain.

Answer 1

SOLUTION: In case of Pull AN AN In case of Push: free Body Diagram, nh m f. = TMENT fk = MKN Sandt ing N=mq mg for accelaration, F-fx = mia F-MKN=ma, velocity is time Equation, a = dire - Folking , F-MKN a = m F - Memy m v=lf-Hic mg) dt to M91 V = 1 ct - - m m m m m (F- Meng) [t-o] - Hemnet Position is time equation, wa che (f-4km) + , x-f (freong Edt **[ Home ] ez Now, accelaratian Vs time graph, all constant a In both cases, the equations t and graphe will be same. velocity is time graph, Iar linear