## Friday, 5 September 2014

### CIRCULAR MOTION SIMPLE PROBLEMS

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.