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:
25 m/s
Explanation:
This question can be solved using equation of motion
where
v is the final velocity
u is the initial velocity
s is the distance covered while moving from initial to final velocity
a is the acceleration
_____________________________________________
Given
box moved for distance of 62.5 m
Friction slows the box at –5.0 m/s2----> this statement means that there is deceleration , speed of truck decreases by 5 m/s in every second until the box comes to rest. Friction causes this deceleration.
thus in this problem
a = -5.0 m/s2
V = 0 as body came to rest due to friction deceleration
u the initial velocity we have to find
the initial velocity of box will be the same as speed of truck, as the box was in the truck and hence box will pick the speed of truck.
so if we find speed of box, we will be able get sped of truck as well.
using equation of motion
Thus, initial speed with the truck was travelling was 25 m/s.