7. When Kim rows her boat, the two oars are both in the water for 3 s and then both out of the water for 2 10. A train acc 120m from the st This 5's cycle is then repeated. When the oars are in the water the boat accelerates at a constant 1.8ms 2 and the train is modelled be ums and the ac when they are not in the water it decelerates at a constant 2.2ms . (i) Find the change in speed that takes place in each 3 s period of acceleration. )By consider (ii) Find the change in speed that takes place in each 2 s period of deceleration. (1i) Find a (iii) Calculate the change in the boat's speed for each 5 s cycle. (iv) A race takes Kim 45 s to complete. If she starts from rest what is her speed as she crosses the finishing line (v) Discuss whether this is a realistic speed for a rowing boat. 8. A ball is dropped from a tall building and falls with acceleration of magnitude 10ms . The distance between floors in the block is constant. The ball takes 0.5 s to fall from the 14th to the 13th floor and 0.3 s to fall from the 13th floor to the 12th. What is the distance between floors? 9. Two clay pigeons are launched vertically upwards from exactly the same spot at 1 s intervals. Each clay pigeon has initial speed 30ms" and acceleration 10ms 2 downwards. How high above the ground do they collide