Answer:
345 N
Explanation:
Given:
Normal weight of Rachel (mg) = 690 N
Case 1: Upward motion of elevator
Given:
Acceleration of elevator (a) = 0.25 g
The scale reading is given by the normal force acting on Rachel. Let N₁ be the normal force.
So, the net force acting on Rachel is given as:
Now, from Newton's second law:
Case 2: Downward motion of elevator
Given:
Acceleration of elevator (a) = 0.25 g
The scale reading is given by the normal force acting on Rachel. Let N₂ be the normal force.
So, the net force acting on Rachel is given as:
Now, from Newton's second law:
Now, the difference in the scale reading is obtained by subtracting equation (2) from equation (1). This gives,
Therefore, the difference between the up and down scale readings is 345 N.