28. The displacement of an object attached to the end of a spring can be modelled by the function 05/ 121+ 7 , where h is the height of the object from the floor, in centimetres, and f is the time, in seconds. Determine the acceleration of the object at time f. (3 marks)29. Find the equation of the tangent to the curve y = 4x - tanx at the point where X = 430. The population ofa bacterial culture was 5000 bacteria after 15 min and 40 000 bacteria after 1 h. a} After how many minutes will the population reach 150 000 bacteria? (3 marks} 1]) Find the rate of growth after 15 min. Express your answer as bacteria per hour