2 A particle is projected vertically upwards with speed \(30 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) from a point on horizontal ground.
- Show that the maximum height above the ground reached by the particle is 45 m .
- Find the time that it takes for the particle to reach a height of 33.75 m above the ground for the first time. Find also the speed of the particle at this time.
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Four coplanar forces of magnitudes \(F \mathrm {~N} , 5 \mathrm {~N} , 25 \mathrm {~N}\) and 15 N are acting at a point \(P\) in the directions shown in the diagram. Given that the forces are in equilibrium, find the values of \(F\) and \(\alpha\).