Question

a) Determine what normal force would be required to accelerate a 100 pound person from ground level at a rate of 2.0 or 3.0m/s^2b) What would the normal force be if the acceleration described in a) was directed downwards?The picture shows the question I need to solve but I answered the first two questions by determining my weight which is 100lbs. I don't know how to go from here.

Answer 1

To solve question 3, we will first make a free body diagram of the situation.

With Newton's second law we can use the following equation

m = 100 lbs = 45.36 kg

`\begin{gathered} N-W=ma \\ N=W+ma \\ N=mg+ma \\ N=m(g+a) \\ N=45.36kg\cdot(9.8m/s^2+3m/s^2) \\ N=580.6\text{ N} \end{gathered}`

For question 4 we are going to use the same equation as above but we are going to modify the direction of the acceleration so we must change its sign.

`\begin{gathered} N=m(g-a) \\ N=45.36kg(9.8m/s^2-3m/s^2) \\ N=308.44N \end{gathered}`