Physics
Physics
Problem
A sledge of mass is pulled along a horizontal snow track by a constant horizontal force of . The coefficient of kinetic friction between the sledge and the snow is . In addition, the sledge experiences a constant resistive force of due to air. (i) Write an expression for the net horizontal force acting on the sledge. (ii) If the sledge starts from rest, calculate the speed it attains after moving along the track. (iii) Determine what fraction of the total work done by the pulling force is dissipated as thermal energy.Intuitive explanation
The key is recognizing that the sledge experiences multiple forces—pulling, friction, and air resistance—all acting horizontally. You'll need to find the net force by adding them as vectors (with careful attention to direction), then use that net force with kinematics or energy methods to find speed and energy dissipation. Think of it as a force-accounting problem: every joule of work from the pulling force either accelerates the sledge or gets lost to heat.
Intuitive explanation
The key is recognizing that the sledge experiences multiple forces—pulling, friction, and air resistance—all acting horizontally. You'll need to find the net force by adding them as vectors (with careful attention to direction), then use that net force with kinematics or energy methods to find speed and energy dissipation. Think of it as a force-accounting problem: every joule of work from the pulling force either accelerates the sledge or gets lost to heat.