Answer:
θ = cos^(-1) (-A/B)
Explanation:
The image of the reauktant forces A & B are missing, so i have attached it.
Now, from the attached image, we will see that;
Angle between A and B is θ
Also;
A = Bcos(180° − θ)
Now, in trigonometry, we know that;
cos(180° − θ) = -cosθ
Thus;
A = -Bcosθ
cosθ = -A/B
Thus;
θ = cos^(-1) (-A/B)
These are exaxmples of a quantitative observation.
Measuring is the expression of an observed quantity in a number with a relevant unit that can be compared with other values of the same quantity.
It is not limited to physical quantities, but extends to a quantitative description of the whole of reality. Measurements are usually quantitative observations, and their results are expressed in
- numerical values, and
- units
Learn more about quantitative observations in brainly.com/question/12042148.
Answer:
42.4 Npa
Explanation:
Explanation is attached in the picture below
This is a concrete example of the Doppler effect. This effect is the change of frequency experienced by the listener or the observer with respect to their relative distance to the source of the sound. There can be two equations to be applied: to the approaching source, and to the receding source.
Approaching source:
frequency observed = [v/(v-v,source)]*frequency of source, where v is the velocity of sound . Substituting,
1000 = [340/(340-v,source)]*frequency of source <---- equation 1
Receding source:
frequency observed = [v/(v+v,source)]*frequency of source, where v is the velocity of sound . Substituting,
800 = [340/(340+v,source)]*frequency of source <---- equation 2
Rearranging equation 1: [1000(340-v,source)]/340 = frequency of source
Equation 2: 800 = [340/(340+v,source)]*frequency of source
Substituting equation 1 to equation 2:
800 = [340/(340+v,source)]*[1000(340-v,source)]/340
Solving using the scientific calculator under shift-solve feature,
v,source = 37.78 m/s
Therefore, the train is moving at 37.78 m/s.