Question

A girl of mass 48.1 kg stands on a weight scale in an elevator that is initially at rest. Etc. Please help.

Answer 1

Given:

Mass, m = 48.1 kg

As the elevator begins to move, the weight = 331 N.

Let's find the acceleration experienced by the girl as the elevator begins to move.

Let's first find the weight of the girl when the elevator was at rest:

`W=m*g=48.1*9.8=471.38\text{ N}`

We can see the actual weight is less than the weight on the scale as the elevator begins to move.

Therefore, there will be a downward acceleration.

Now, apply the formula:

`N=mg-ma`

Where:

N = 331 N

m = 48.1 kg

g is acceleration due to gravity = 9.8 m/s²

Plug in values in the formula and solve for a:

`\begin{gathered} N=m(g-a) \\ \\ 331=48.1(9.8-a) \\ \\ (331)/(48.1)=9.8-a \\ \\ a=9.8-(331)/(48.1) \\ \\ a=9.8-6.88 \\ \\ a=2.92\text{ m/s}^2 \end{gathered}`

Therefore, the acceleration is -2.92 m/s²

ANSWER:

-2.92 m/s²