2 A particle \(P\) is projected down a line of greatest slope on a smooth inclined plane. \(P\) has velocity \(5 \mathrm {~ms} ^ { - 1 }\) at the instant when it has been in motion for 1.6 s and travelled a distance of 6.4 m . Calculate

1. the initial speed and the acceleration of \(P\),
2. the inclination of the plane to the vertical.