A. floor is smooth and wall is rough
B. floor is rough and wall is rough
C. both floor and wall are rough
D. both floor and wall are smooth
Correct Answer: ✔
Last Updated: January 18, 2019
A. floor is smooth and wall is rough
B. floor is rough and wall is rough
C. both floor and wall are rough
D. both floor and wall are smooth
Correct Answer: ✔
Last Updated: January 18, 2019