K.C.S.E Physics Q & A - MODEL 2013PP1QN14

K.C.S.E Physics Q & A - MODEL 2013PP1QN14

​(a) State two ways in which the centripetal force on a body of mass m can be increased 
(b) Figure 7 shows an object at the end of a light spring balance connected to a peg using a string. The object is moving in a circular path on a smooth horizontal table with a constant speed.

​(i) State what provides the centripetal force. 
(ii) Indicate with an arrow on the figure the direction of the centripetal force. 
(iii) State a reason why the object is accelerating while its speed remains constant. 
(iv) Given that the mass of the object is 0.5 kg and it is moving at a speed of 8 m/s at a radius of 2 m, determine the reading on the spring balance. 
(c) A stone thrown vertically upwards reaches a height of 100 m. Determine the:
(i) initial velocity of the stone. 
(Neglect air resistance and take g =10m/s2)
(ii) total time the stone is in air. 

answers

(a) - increasing the angular velocity;
- Reducing the radius of the path; 
(b) (i) Tension in the string; 
(ii) Arrow to centre of circle; 
(iii) Direction of motion of object changes and causes the velocity to change with time;