A swimming duck paddles the water with its feet once per time interval of 2.0 s, producing surface waves with this period. The d
uck is moving at constant speed in a pond where the speed of surface waves is 0.30 m/s, and the crests of the waves ahead of the duck have a spacing of 0.20 m.
1 answer:
Answer:
Part A: What is the duck's speed? v=0.2m/s
Part B: How far apart are the crests behind the duck = 1m
Explanation:
The concept applied here is the DOPPLER EFFECT, for example, if one is driving towards a station at 120km/hr, a higher frequency will be heard. and if you are driving away from the station at the same speed, one will hear a much more lower frequency. Tthese effect was proposed by the Austrian physicist by name Johann Christian doppler.
The detailed steps and appropriate formula is as shown in the attached file.
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Answer:
v= 14.85 m/s
Explanation:
- When at the bottom of the dip, the only force that keeps the car in the circular trajectory, is the centripetal force.
- This force is not a new force, is just the net force aiming to the center of the circle.
- In this case, is just the difference between the normal force (always perpendicular to the surface, pointing upward) and the force that gravity exerts on the car (which is known as the weight), pointing downward.
- So, we can write the following expression:
- It can be showed that the centripetal force is related to the speed by the following expression:
- The normal force, it is called the apparent weight, because it would be the weight as measured by a scale.
- Replacing (2) in (1), and solving for Fn, we get:
- Now, we need to find the value of v that makes Fn, exactly 15% more than the weight m*g, so we can write the following equation:
- Replacing Fg by its value, simplifying, and solving for v, we get: