K.C.S.E Physics Q & A - MODEL 2013PP1QN16

K.C.S.E Physics Q & A - MODEL 2013PP1QN16

​ (a) A horizontal force of 12 N is applied on a wooden block of mass 2 kg placed on a horizontal surface. It causes the block to accelerate at 5 m/s2. Determine the frictional force between the block and the surface. (3 marks)
(b) Figure 9 shows a graph of velocity against time for a ball bearing released at the surface of viscous liquid.

​Explain the motion of the ball bearing for parts
(I) OA 
(ii) AB 
(c) Figure 10 shows a pulley system used to raise a load by applying an effort of 500 N.

​State the:
(i) velocity ratio of the system. 
(ii) purpose of pulley 2.
(iii) Given that the machine has an efficiency of 80%, determine the maximum load that can be raised. 

answers

​(b) (I) OA - the ball bearing decelerates; as the upthrust increases to a maximum;
AB - baIl attains terminal velocity; when upthrust = weight;