Please type them, don't write the answers on paper.

9. A construction worker accidently drops a hammer from a height of 90 m while working on the roof of a new apartment building. The height, 3, in metres, of the hammer aftert seconds can be modelled by the function s(t)=904.9t2, 1: >0. a. Determine the velocity at 1 s and 4 s. (1 mark) b. When will the hammer hit the ground? (1 mark) c. Determine the impact velocity of the hammer. (1 mark) 10. The motion of a particle is described by the position function S(t)=2t315t2+33t+17,t>0 , where r is measured in seconds and s(t) in metres. a. When is the particle at rest? (2 marks) b. When is the velocity positive? (2 marks) c) Draw a diagram to illustrate the motion of the particle in the first 10 seconds. (1 mark) d) Find the total distance traveled in the first 10 seconds. (1 mark) 11. A snowball melts so that its surface area decreases at a rate of 0.5 cmzfmin. Find the rate at which the radius decreases when the radius is 4 cm. (SA=4r:r2] (4 marks)