Module Ge1

							                                   Module Ge1

                           How and why things move

These questions concentrate on the formula you are expected to remember!


   1. Write down the formula for MOMENTUM

Calculate the momentum of the following objects.
Give the units for your answers

   (a) A car of mass 10000 kg travelling at a velocity of 50 m/s
   (b) A cyclist of total mass 75 kg travelling at a velocity of 8m/s
   (c) A train of mass 200000 kg travelling at a velocity of 85 m/s


   2. Write down the formula for CHANGE of MOMENTUM, in terms of the
      resultant force acting on an object and the time for which it acts.

   Calculate the change of momentum of the following objects

   (a) A resultant force of 50 N acting for 5 seconds
   (b) A resultant force of 120 N acting for one minute
   (c) A resultant force of 1200 N acting for 1 hour


   3. Explain two ways of reducing the impact force of collision for cars.
      (Consider the safety features). Explain, using the formula in (2), why
      these reduce the impact force.


   4. Write down the formula for WORK DONE by a force

Calculate the work done when

   (a) A resultant force of 50 N moves an object through 50 m
   (b) A resultant force of 250 N moves an object through a distance of 100 m
   (c) A forward force of 500 N acts against a resistive force of 200 N for a
       distance of 100 m

   5. Write down the formula for the change of gravitational potential energy

Calculate the change in Potential Energy when

   (a) An object of mass 20 kg is lifted through a height of 100 m
   (b) An object of weight 200N is lifted from 25m to 100m
   (c) An object of mass 120 kg is lifted from 100m to 150 m

   ( Remember! Weight = mass x gravitational acceleration )