Question 17 (3 points) The Jackass crew built a very small loop-the-loop for one of their shows. They can get their small mini-bikes up to 18 m/s before they enter the loop. What is the biggest possible loop they could make it around (to the nearest tenth of a meter)? Assume they maintain their speed around the entire loop. Your Answer: Answer Question 18 (5 points) Three masses are placed in a line as shown below. It was found that the net force acting on M2 is 4x10-3 N [left]. Calculate (to one tenth of a cm) the centre-to-centre separateion of M2 and m1. The diagram is not to scale. m1 = 1000kg m2 = 100kg m3 = 500kg O O C 71,2 12,3 = 5cm A/Question 19 (5 points) Astrophysicists have observed a planet orbiting a star in a distant galaxy. The orbital period of this planet is 25 years and its mean radius of orbit is 5.5 x 10 2 m. Determine the mass of the star. Your Answer: Answer Question 20 (5 points) An Australian hunter hunts kangaroos with the following weapon, a heavy rock (1.5kg) tied to one end of a light vine of length 2 metres. He holds the other end above his head and swings the rock in a nearly horizontal circle. The hunter knows that the vine always breaks when the angle, , (measured between the vine and the horizontal) reaches 30. What is the maximum speed (in m/s, to one decimal place) with which the bushman can twirl the rock so the vine won't break? Include a FBD in your answer. Hint: It is the horizontal component of tension providing the centripetal force. 30 L = 2m O