A cube shaped block, 25 cm tall, is pulled over a horizontal and stationary surf
ID: 1525964 • Letter: A
Question
A cube shaped block, 25 cm tall, is pulled over a horizontal and stationary surface at a constant kg speed of 0. 7 m/s accross a layer of fluid 0.04 mm thick. This fluid has a viscosity of 0.04 m S a. Assuming a linear distribution of speed between the stationary surface and the moving block, calculate the magnitude of the force needed to pull the block at the given speed b. Instead of a linear distribution of speed between the stationary surface (z 0 mm) and the block (z d 04 mm where u ublock (i) assume that the speed distribution is non ear, given by u ublack How does the magnitude of the In force required to push the block at the given speed depend on the value of r, assuming r 1 c. Does a larger value of r make the flow profile more steep or less steep? d. On the same graph, plot the flow profile u(z) for the values r r-2, r-7, and r-10. Plot z on the vertical axis and u on the horizontal axis.
5. A cube shaped block, 25 cm tall, is pulled over a horizontal and stationary surface at a constant kg speed of 0.7 m/s accross a layer of fluid 0.04 mm thick. This fluid has a viscosity of 0.04 min S a. Assuming a linear distribution of speed between the stationary surface and the moving block, calculate the magnitude of the force needed to pull the block at the given speed. b. Instead of a linear distribution of speed between the stationary surface (z 0 mm) and the block (z d a. 04 mm) where u ublock assume that the speed distribution is non-linear, given by u ublock (4 How does the magnitude of the force required to push the block at the given speed depend on the value of r, assuming r 2 1 c. Does a larger value of r make the flow profile more steep or less steep? d. On the same graph, plot the flow profile u(z) for the values r 1, r 2, r-7, and r 10. Plot z on the vertical axis and u on the horizontal axis.Explanation / Answer
a) the magnitude of the force needed = 0.04 * 0.25 * 9.8/0.7
= 0.14 N
b) magnitude of the force = 0.05/r2
c) Less steep .