Answer:The frequency of the echo is slightly decreased
Explanation:
Given
speed of boat 
cliff is 
away
when boat is still , suppose t is the time taken by the echo to reach observer on the boat
But as soon as boat starts moving the distance between cliff and boat decreasing and time for echo to reach observer also decreases
and we know 
therefore frequency of the echo slightly decreased.
Answer:
hydrogen
helium
oxygen
Explanation:
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Answer:
Technique of comparing abundance ratio between radioactive isotopes to a reference isotope to determine the age of a material called radioactive dating. It determines the age by having a more abundance of isotopes in the cellular being.
Answer:
Final speed of boat + man is 1.66 m/s
Explanation:
As we know that there is no friction on the system or there is no external force on this system
So here we can use momentum conservation here
so we have
m = 85 kg
M = 135 kg
v = 4.30 m/s
now we have
Velocity of an object is its rate of change of the object's position per interval of time. Velocity is a vector quantity which means that it consists of a magnitude and a direction. Magnitude is represented by the speed and the direction is represented by the angle. To determine the velocity components, we use trigonometric functions to determine the angle of the components. For the north component we, use the sine function while, for the west component, we use the cosine function. We calculate as follows:
north velocity component = (16.8 m/s) (sin 54°) = 16.4 m/s
<span>west velocity component = (16.8 m/s) (cos 54°) = 3.49 m/s</span>
