An apple weighs $1\mathrm{.}20$ NN $.$ When you hang it from the end of a long spring of force constant $1\mathrm{.}60$ N$/$mN$/$m and negligible mass, it bounces up and down in SHM$.$ If you stop the bouncing and let the apple swing from side to side through a small angle, the frequency of this simple pendulum is half the bounce frequency. $($Because the angle is small, the back and forth swings do not cause any appreciable change in the length of the spring.$)$ An apple weighs $1\mathrm{.}20$ NN $.$ When you hang it from the end of a long spring of force constant $1\mathrm{.}60$ N$/$mN$/$m and negligible mass, it bounces up and down in SHM$.$ If you stop the bouncing and let the apple swing from side to side through a small angle, the frequency of this simple pendulum is half the bounce frequency. $($Because the angle is small, the back and forth swings do not cause any appreciable change in the length of the spring.$)$