Question

1. a student stands on a platform scale inside of an elevator. the student has a mass of 70 kg.

a. the student presses a button to go up from the first floor to the 20th floor.
i. initially the elevator must have an acceleration that points ___ as it starts to move.
ii. draw a fbd for the forces acting on the student during this time.
iii. what type of force does a platform scale measure?
iv. during this time the platform scale has a reading of 1036 newtons. write a sum of the forces and use it to calculate the acceleration of the student inside the elevator.

Explanation:

Step1: Determine the direction of acceleration

When the elevator starts to move up, the acceleration is in the upward direction.

Step2: Draw the Free - Body Diagram (FBD)

The forces acting on the student are the gravitational force \(F_g = mg\) (acting downwards, where \(m = 70\space kg\) and \(g=9.8\space m/s^{2}\)) and the normal force \(N\) (acting upwards, which is the force measured by the scale).

Step3: Identify the force measured by the scale

The platform scale measures the normal force \(N\) exerted on the student.

Step4: Apply Newton's second law

Newton's second law is \(\sum F = ma\). The sum of the forces is \(N - mg=ma\).
We know \(N = 1036\space N\), \(m = 70\space kg\) and \(g = 9.8\space m/s^{2}\).
Substitute the values into the equation:

$$
LATEXBLOCK0
$$

Answer:

i. Upward
ii. FBD: A dot representing the student with a downward arrow labeled \(F_g=mg\) and an upward arrow labeled \(N\)
iii. Normal force
iv. The acceleration \(a = 5\space m/s^{2}\)