3
\includegraphics[max width=\textwidth, alt={}, center]{7958ad9d-1a28-439d-8de0-5039f2dba770-2_255_926_1073_614}
One end of a light inextensible string is attached to a fixed point \(A\) and the other end of the string is attached to a particle \(P\). The particle \(P\) moves with constant angular speed \(5 \mathrm { rad } \mathrm { s } ^ { - 1 }\) in a horizontal circle which has its centre \(O\) vertically below \(A\). The string makes an angle \(\theta\) with the vertical (see diagram). The tension in the string is three times the weight of \(P\).
- Show that the length of the string is 1.2 m .
- Find the speed of \(P\).
\includegraphics[max width=\textwidth, alt={}, center]{7958ad9d-1a28-439d-8de0-5039f2dba770-3_521_1004_258_575}
A small ball \(B\) is projected from a point \(O\) above horizontal ground, with initial speed \(15 \mathrm {~ms} ^ { - 1 }\) at an angle of projection of \(30 ^ { \circ }\) above the horizontal (see diagram). The ball strikes the ground 3 s after projection. - Calculate the speed and direction of motion of the ball immediately before it strikes the ground.
- Find the height of \(O\) above the ground.