A roller coaster enters a loop$-$de loop on its track and experiences no mechanical acceleration when it is in the loop$-$de$-$loop fi$.$e no further acceleration is provided va moton or eiectricity$).$ It enters the loop at a velocity of ven is$.$ As the roller coaster travels through the loop, it experiences a normal force acting against it from the track. Assume the track at this section to be perfectly circular with a radius