1.A small ball of mass
+ y ;i7 u6pqi8pr/*enkiwi3ml $m$ is oscillating on a frictionless curved surface.
$x$ is the horizontal displacement from the middle point $O$ of the motion. The shape of the surface is such that the relationship between net force in the horizontal axis and displacement is given by the expression
$F=-m\frac{gx}{r}$
where g is the acceleration of free-fall and r is the radius of the curvature of the surface.
Outline why the ball performs simple harmonic motion.
2.The radius r of the frictionless surface and the mass m of the ball are $10\,cm$ and $20\,g$ respectively.
(1)
Show that $ω=\sqrt{\frac{g}{r}}$
(2)Calculate, in $s$, the time taken for the ball to reach point $O$ after being released from the highest point.
The time needed for the motion= s
(3)Draw, on the axes, the graph to show how the kinetic energy of the ball varies with displacement during its motion from the start until it reaches point $O$. Be sure to include the values for the vertical and horizontal intercepts.