$6$

Multiple Answer

$10$ points

A ball of mass $m$ moves along a track in the shape of vertical circular loop. There are $2$ forces acting on the ball $--$ the normal force exerted by track $(N_{\text{t}\text{r}\text{a}\text{c}\text{k}})$ and gravity $).$ Ignore friction and air resistance.

The vectors vec$(v)($velocity$)$ and vec$(a)($total acceleration$)$ have an angle $$ between them, which changes as the ball moves.

Check all the answers which are true statements. There may be more than one correct answer!

when the ball is on the way up the loop, $>90$

$=90$ at the "side" points $($halfway up the loop$)$

the ball falls off the track if $N_{\text{t}\text{r}\text{a}\text{c}\text{k}}=0$

the magnitude of vec$(a)$ is always smaller than $g,$ no matter how fast the ball moves

at the bottom of the loop, $N_{\text{t}\text{r}\text{a}\text{c}\text{k}}$ is stronger than $mg$