1.A construction worker accidentally drops a hammer from a height of 90 m while working

on the roof of a new apartment building. The height, s, in metres, of the hammer after t

seconds can be modelled by the function s(t)= 90 - 4.9t^2 , t > 0 . (Explain)

a. Determine the velocity at 1 s and 4 s.

b. When will the hammer hit the ground?

c. Determine the impact velocity of the hammer.

2.The motion of a particle is described by the position function s(t)=2t^3 - 15t^2 +33t +17 , t>0 , where t is measured in seconds and s(t) in meters. (Explain)

a. When is the particle at rest?

b. When is the velocity positive?

c. Draw a diagram to illustrate the motion of the particle in the first 10 seconds.

d. Find the total distance traveled in the first 10 seconds.

3.A snowball melts so that its surface area decreases at a rate of 0.5 cm^2/min . Find the rate at which the radius decreases when the radius is 4cm. (SA=4r²). (Explain)