State the two conditions for a system to be in equilibrium.

1. (a)State the two conditions for a system to be in equilibrium.[2]
2. (b)A paraglider P of mass 95kg is pulled by a wire attached to a boat, as shown in Fig. 2.1. [Figure 2.1] The wire makes an angle of 25° with the horizontal water surface. P moves in a straight line parallel to the surface of the water. The variation with time t of the velocity v of P is shown in Fig. 2.2. [Figure 2.2]
3. (b)(i)Show that the acceleration of P is 1.4 m s⁻² at time t = 5.0 s.[2]
4. (b)(ii)Calculate the total distance moved by P from time t = 0 to t = 7.0 s.[2]
5. (b)(iii)Calculate the change in kinetic energy of P from time t = 0 to t = 7.0 s.[2]
6. (b)(iv)The tension in the wire at time t = 5.0 s is 280N. Calculate, for the horizontal motion,
7. (b)(iv)1.the vertical lift force F supporting P,[3]
8. (b)(iv)2.the force R due to air resistance acting on P in the horizontal direction.[3]

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