Question

Figure 8 shows a bucket filled with water and tied to one end of a string which is used to whirl it in a vertical circular path with a uniform speed v.

 

1. State two forces acting on the bucket at any instant. 
2. Explain why the tension is lowest at point A. 
3. The speed of the bucket is gradually reduced. Explain what is likely to be observed when the bucket is at point A.
4. A stone of mass 40g is whirled at the end of a string in a horizontal circular path at (b) speed of 12ms^-1. (The string and the stone are in the same horizontal plane). If the string is 1m long, determine the tension in the string. (3 marks)

Answer 1

1.     
   • Weight  of the bucket/ force of gravity/ Gravitational force
   • Tension on the string 
2. Part of the centripetal force required is provided by the weight / both tension & weight act in the same direction therefore tension will be less.
3.  
   • Water is likely to pour out
   • At a certain minimum speed, the centripetal force is less than what is required to keep the motion, therefore, some water spills out./ The body is moving at a speed less than the critical speed.
4.   F= T = mv² 
                  r
   = 0.04 x 12 x12  
                1
   =5.76N