Shelley is in an elevator that is traveling downward and slowing down at a rate of
1 answer:
Answer:
N = 648.55[N]
Explanation:
To solve this problem we must use Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
∑F = m*a
where:
∑F = Forces applied [N]
m = mass = 73.2 [kg]
a = acceleration = 0.950 [m/s²]
Let's assume the direction of the upward forces as positive, just as if the movement of the box is upward the acceleration will be positive.
By performing a summation of forces on the vertical axis we obtain all the required forces and other magnitudes to be determined.
where:
g = gravity acceleration = 9.81 [m/s²]
N = normal force (or weight) measured by the scale = 83.4 [N]
Now replacing:
The acceleration has a negative sign, this means that the elevator is descending at that very moment.
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Answer:
a) x_average = ∑ / n
, b) Δx_{i} = x_{i} –x_average,
d) σ = √(1/n-1 ∑ Dx_{i}² )
Explanation:
Some definitions are requested
a) the average value is the sum of all the values divided by the number of them, if the uncertainties are random, this is the closest value to the real one
x_average = ∑ / n
b) The deviation from the mean value or absolute error is the measured value minus the average value
Δx_{i} = x_{i} –x_average
c) is the average value of the deviations
Δx_average = ∑ Δx_{i} / n
d) It is a measure of the dispersion of the values with respect to their average value, it takes the worst of all cases, widely used for large numbers of data
σ = √(1/n-1 ∑ Dx_{i}² )
Experimental results should be given as follows
Average value ± uncertainty and the standard deviation
(x_average + - Δx_average)
σ