- #1

- 9

- 0

- Homework Statement
- block on block fricton , and inclined plane in elevator

- Relevant Equations
- f=ma

hello , I am adding pdf with the questions and what i tried to do to solve them.

in the first question my teacher just taught us that if there is a frictionless floor and i push the upper block (m) with force F toward me then if the static friction will be toward me too. so the lower block M is going to go the opposite way of the force and i don't understand how it is logical. and if the m slide on M then its kinetic friction and the directions of the friction switch so the friction would be againt the F.

in short my question is if someone can give me a better explination about this specific problem.

in the second question i struggle to understand how to set the X and Y axis and the forces and what is Normal force if the elevator accelerates upward with a.

in the first question my teacher just taught us that if there is a frictionless floor and i push the upper block (m) with force F toward me then if the static friction will be toward me too. so the lower block M is going to go the opposite way of the force and i don't understand how it is logical. and if the m slide on M then its kinetic friction and the directions of the friction switch so the friction would be againt the F.

in short my question is if someone can give me a better explination about this specific problem.

in the second question i struggle to understand how to set the X and Y axis and the forces and what is Normal force if the elevator accelerates upward with a.