**Take g = 9.8 Nkg**

^{-1}

**1. Write down three things that travel in a circle stating each time the type of force needed to give circular motion. (THEY MUST BE DIFFERENT TYPES OF FORCE)**

**2. Which of the following correctly describe the motion of a satellite in orbit round the Earth:**

**(a) constant speed (b) constant velocity (c) constant acceleration (d) constant accelerating force**

**3. Why do astronauts feel heavier in a centrifuge?**

**4. What is the name of the force that makes objects move in a circle?**

**5. A stone of mass 4kg is tied to string and swung in a horizontal circle of radius 2m with a speed of 4ms**

^{-1}.**(a) what is the force on the stone?**

**(b) how many revolutions does the stone make every second?**

**(c) in what direction will the stone move if the string is cut?**

**(d) what will the force become if the radius of the orbit is halved?**

**6. The force of friction between a certain car and the road is 10 000N. If the mass of the car is 1000 kg what is the maximum speed that it can take a corner of radius 40m?**

**7. How can a stone on the end of a string be spun round at a constant speed and yet still experience a force?**

**8. Describe carefully the effect on the passengers in a bus that corners quickly. Your answer should include a plan view to show which way the passengers move.**

**9. Calculate the acceleration of a 3kg mass travelling in a circle of radius 2m at a constant speed of 6ms**

^{-1}.**10. A stone is swung round in a vertical circle. At which point in the circle is the string most likely to break and why?**

**11. “A satellite in orbit is continually falling round the Earth”. Explain this statement.**