Tutorial: Circular motion III. Non-constant circular motion A skateboarder (mass 45 kg) starts from the top of a quarter pipe (i.e., a quarter circle) of radius 2.0 m, and when he is at the position shown below, he has a speed of 3.0 m/s. Your goal is to calculate his centripetal acceleration, tangential acceleration, and the normal force acting on him when he is at the position shown. Friction at the wheels of the skateboard is negligible. To do this we will follow the problem solving strategy outlined in the previous pages. A. Draw a free body diagram on the skateboarder on the diagram to the right. B. Choose an xy coordinate system. Add this to your diagram above. Hint: What is the direction of the centripetal acceleration at the point indicated? C. Break up any forces not along the directions chosen and gure out the components in terms of the 30 angle shown. Draw the components on the figure and write down what they are equal to below. (For example, if you choose to break up the normal force, you might have N3, = N sin 30) D. Write down Newton's 2\"d law for the x direction chosen. E. Write down Newton's 211d law for the y direction chosen. F. Calculate the centripetal acceleration. This is very simple to do, you don't need either of the equations written above. G. Calculate the tangential acceleration. Use one of your equations from either D or E. H. Calculate the normal force acting on the skateboarder. Use the other equation. I. Suppose the skateboarder trips at the point indicated and is sliding on the quarter pipe at the same speed (3.0 m/s). The coefficient of kinetic friction between his clothes and the 30 track is 0.25. Your goal is to calculate his tantengial acceleration in this situation. a. Draw the same free body diagram you did above, and add the force of kinetic friction. b. One of the equations from before doesn't change. The other does. Write the changed equation below. c. Calculate the force of kinetic friction. d. Calculate his tangential acceleration in this situation