An acrobat swings on a 32.0 m long cable initially inclined at an angle of 39.00 with the vertical. (Assume the cable has negligible mass.) (a) What is the acrobat's speed (in m/s) at the bottom of the swing if she starts from rest? m/s (b) What is the acrobat's speed (in m/s) at the bottom of the swing if instead she pushes off with a speed of 5.20 m/s? m/sYou wish to make a simple amusement park ride in which a steel-wheeled roller-coaster car travels down one long slope, where rolling friction is negligible, and later slows to a stop through kinetic friction between the roller coaster's locked wheels sliding along a horizontal plastic (polystyrene) track. Assume the roller-coaster car (filled with passengers) has a mass of 758.0 kg and starts 75.0 m above the ground. (a) Calculate how fast the car is going when it reaches the bottom of the hill. 38.34 v m/s (b) How much does the thermal energy of the system change during the stopping motion of the car? 557113.17 J (c) If the car stops in 236.33 m, what is the coefficient of kinetic friction between the wheels and the plastic stopping track?Shawn (m = 43.5 kg) rides his skateboard at a local skate park. He starts from rest at the top of the track as seen in the figure below and begins a descent down the track, always maintaining contact with the surface. The mass of the skateboard is negligible, as is friction except where noted. FK 12.0 m 8.0 m 18.0 m (a) What is Shawn's speed when he reaches the bottom of the initial dip, 12.0 m below the starting point? m/s (b) He then ascends the other side of the dip to the top of a hill, 8.0 m above the ground. What is his speed when he reaches this point? m/s c) As he begins to descend again, down a straight, 18.0-m-long slope, he slows his skateboard down by using friction on the tail of the board. He is able to produce a friction force with a magnitude of 116.0 N. What is the change in thermal energy of the board-rider-track system as he descends the 18.0-m length of track? (d) What is his speed when he reaches the bottom (the end of the 18.0-m length of track)? m/sAn 80.0-kg skydiver jumps out of a balloon at an altitude of 1,110 m and opens the parachute at an altitude of 190.0 m. (a) Assuming that the total retarding force on the diver is constant at 50.0 N with the parachute closed and constant at 3,600 N with the parachute open, what is the speed of the diver when he lands on the ground? m/s (b) Do you think the skydiver will get hurt? Explain. This answer has not been graded yet. (c) At what height should the parachute be opened so that the final speed of the skydiver when he hits the ground is 5.70 m/s? m (d) How realistic is the assumption that the total retarding force is constant? Explain. This answer has not been graded yet