1. The problem statement, all variables and given/known data An object, moving along the circumference of a circle with radius ##R##, is acted upon by a force of constant magnitude F. The force is directed at all times at a ## 30 \degrees ## angle with respect to the tangent to the circle. Determine the work done by this force when the object moves along the half circle from A to B. 2. Relevant equations N/a 3. The attempt at a solution My solutions guide tells me to us ##\int (Fcos \theta dl)## The question stated "constant force", so why do we need to integrate? Why can't I use F dot D? Thank you! By the way, how do I write in limits for integration?