4. Two skaters are at a circular outdoor skating rink with a radius of 25 m. As they cross the centre of the rink, one skater grabs onto the other one. Prior to the collision one skater (with a mass of 55 kg) is travelling northwards at 3.5 m/s. The other skater (with a mass of 60 kg) had been heading east at 2.0 m/s. a) What is the velocity (magnitude + direction) of the two skaters after the collision? (4 marks) b) How long will it take the skaters to reach the edge of the rink if they remain stuck together? Note that to answer this question, you can note that the skaters will move with a constant speed after the collision and along a radial line as they collided at the centre of the rink. (1 mark)