Answer:
Vr = 20 [km/h]
Explanation:
In order to solve this problem, we have to add the relative velocities. We must remember that velocity is a vector, therefore it has magnitude and direction. We will take the sea as the reference measurement level.
Let's take the direction of the ship as positive. Therefore the boy moves in the opposite direction (Negative) to the reference level (the sea).
Answer:
Explanation:
When a standing wave is formed with six loops means the normal mode of the wave is n=6, the frequency of the normal mode is given by the expression:
Where is the length of the string and
the velocity of propagation. Use this expression to find the value of
.
The velocity of propagation is given by the expression:
Where is the desirable variable of the problem, the linear mass density, and
is the tension of the cord. The tension is equal to the weight of the mass hanging from the cord:
With the value of the tension and the velocity you can find the mass density:
Answer:
95 %
99.7 %
Explanation:
= 166 cm = Mean
= 5 cm = Standard deviation
a) 156 cm and 176 cm
From the empirical rule 95% of all values are within 2 standard deviation of the mean, so about 95% of men are between 156 cm and 176 cm.
b) 151 cm and 181 cm
The empirical rule tells us that about 99.7% of all values are within 3 standard deviations of the mean, so about 99.7% of men are between 151 cm and 181 cm.