The path r(t)= (t-sin t) i +( 1 - cos t) j describes motion on the cycloid x=t-sin t, y=1- cos t. Find the particle's velocity and acceleration vectors at t equals pi, and sketch them as vectors on the curve.

Gravity is pulling an object into the sun. the closer the object gets to the sun, the greater the gravitational force that acts on the object, increasing its acceleration. a line graph plotting the speed of the object against time would have which shape? a: straight line of positive slope b: curved line that slopes upward c: curved line that slopes downward d: straight line of negative slope