STATIC

Topic            : Statics

Purpose         : To determine the coefficient of static friction between two surfaces

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Part I: To determine the relationship between the mass of load and the length of spring

(a) Hook one end of the spring on the retort stand and hang the 50 g mass hanger with a 100 g slotted mass at the other end of the spring. Measure the length  l of the spring. Record the mass (the mass hanger and the slotted mass).

(b) Increase the mass m and measure the corresponding length of the spring.

(c) Tabulate m and  l

(d) Plot a graph of against m and  l



Part II: To determine the coefficient of friction between two surfaces

(a) Weigh the mass of the wooden block having a smooth surface. Record down the mass.

(b) Adjusting the retort stand, the angle of inclination for the inclined plane could be changed. An angle of inclination is to be obtained such that the wooden block slide down freely with acceleration. Set up the apparatus as in figure 4. Measure and record the angle of inclination θ.

(c) Displace the wooden block downward and release, so that the wooden block will be pulled to move upward by tension in the spring.

 (d) Repeat step (c) with smaller displacements until a stage that the wooden block stays stationary upon released. Measure and record the length of the spring.

(e) The mass of the wooden block could be increased by adding other wooden blocks on top of the first. Weigh and record the new combined weight m of the block. Repeat steps (c) and (d).

(f) Tabulate m, , and m′ where m′ is the corresponding mass for the length  from the graph against .

(g) Plot a graph of m′ against m.

(h) Calculate the gradient of graph m′ against m and hence determine the coefficient of static friction μ.