(a) The image on the left shows a Wilhelmy plate force tensiometer of width w = 2 cm and the depth d = 2 mm being used to measure the surface tension of water at 25 C. What is the value of the downward force F if the contact angle is 30 when the plate is being withdrawn from the water and we neglect the weight of the plate? F w air liquid (b) (c) Source: Image by Vincent myde () List one advantage and one disadvantage of replacing the rectangular plate with a cylindrical rod with radius r and length L (as shown below)? (c) Write down the equation for determining the surface tension using the cylindrical rod force tensiometer in part (b). In 150 words of less, explain how the equation is obtained. (a) The image on the left shows a Wilhelmy plate force tensiometer of width w = 2 cm and the depth d = 2 mm being used to measure the surface tension of water at 25 C. What is the value of the downward force F if the contact angle is 30 when the plate is being withdrawn from the water and we neglect the weight of the plate? F w air liquid (b) (c) Source: Image by Vincent myde () List one advantage and one disadvantage of replacing the rectangular plate with a cylindrical rod with radius r and length L (as shown below)? (c) Write down the equation for determining the surface tension using the cylindrical rod force tensiometer in part (b). In 150 words of less, explain how the equation is obtained