This is a suggested answer to the GCE O Level Pure Physics examination, year 2014, Paper 1, multiple choice question 7.

The question stated that a cable of crane is used to lift a load. The following information were provided:

  • Mass of load =500kg
  • Weight of load =5000N
  • The Cable exerts a force of 7500N

The student is required to calculate the acceleration of the load.

Suggested Solution

Answer is A . That is, 5 m/s2

Explanation:

When the load is being lifted up, there is a resultant force. The resultant force is the result of the two forces:

Weight of the load, given as:

      W=5000N

And force exerted on the load by the cable which is given as: 7500N.

The resultant force is therefore 7500N-5000N =2500N

However, the formula of resultant force is:

Resultant Force, F = Mass x acceleration

       hence, the acceleration, a   = 2500N/500kg

    = 5 m/s2