The force applied to the cart in Question 5 by spring scale F1 is still 10.5 N. The cart now moves toward the right with a constant velocity. What are the magnitude and direction of the frictional force? Show your calculations and explain your reasoning.

6. The force applied to the cart in Question 5 by spring scale F1 is still 10.5 N. The cart now moves toward the right with a constant velocity. What are the magnitude and direction of the frictional force? Show your calculations and explain your reasoning.
7. The force applied to the cart in Question 5 by spring scale F1 is still 10.5 N. The cart now moves toward the right with an acceleration also toward the right of 1.75 m/s2. What are the magnitude and direction of the frictional force? Show your calculations and explain.
8. The force applied to the cart by spring scale F1 is 10.5 N. The cart now moves toward the right with a constant velocity. The frictional force has the same magnitude as in Question 7. What does spring scale F2 read? Show your calculations and explain.
In Questions 6 – 8, friction may not be ignored.