Question
The 70.0-kg swimmer in Figure 7.43 starts a race with an initial velocity of 1.25 m/s and exerts an average force of 80.0 N backward with his arms during each 1.80 m long stroke. (a) What is his initial acceleration if water resistance is 45.0 N? (b) What is the subsequent average resistance force from the water during the 5.00 s it takes him to reach his top velocity of 2.50 m/s? (c) Discuss whether water resistance seems to increase linearly with velocity.
Question Image
1. $0.500\textrm{ m/s}^2$
2. $62.5 \textrm{ N}$
3. No, the change in water resistance is not linear with respect to speed. The slope of the resistance vs. velocity graph changes with velocity.
Solution Video