4 A particle of mass 3 kg is attached to one end of a light inextensible string. The other end of the string is attached to a fixed point on a smooth horizontal surface.
The particle is set into motion so that it moves with a constant speed \(4 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) in a circular path with radius 0.8 metres on the horizontal surface. 4

1. Find the acceleration of the particle.
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2. Find the tension in the string.
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3. Show that the angular speed of the particle is 48 revolutions per minute correct to two significant figures.