Answer:
Time, 
Explanation:
The speed of sound in the tissue is 1450 m/s and the depth of the fragment is 0.265 m.
It is required to find the time between the transducer emitting the sound and picking the sound echo up. The time taken by the sound is :
So, the time between the transducer emitting the sound and picking the sound echo up is 
If the initial PE is mgh(initial) and the final PE is mgh(final) then mgh(initial)-mgh(final) should give you your change in PE.
So, without conversions your answer should be
[(.08)(9.8)(8)]-[(.08)(9.8)(6)]=change in PE which is 1.568Joules.
Radiation is the correct answer
Answer:
The distance from the pivot point that the small child will sit in order to maintain the balance is 1.8 m
Explanation:
Given;
mass of the bigger child, M = 30 kg
mass of the smaller child, m = 20 kg
distance between the two children, d = 3 m
This information can be represented diagrammatically;
3m
|<------------------------------------------------>|
----------------------------------------------------------------------------
↓ x Δ 3-x ↓
20kg 30kg
x is the distance from the pivot point that the small child will sit in order to maintain the balance
Take moment about the pivot;
Clockwise moment = anticlockwise moment
30(3-x) = 20x
90 -30x = 20x
90 = 20x + 30x
90 = 50x
x = 90 / 50
x = 1.8 m
Therefore, the distance from the pivot point that the small child will sit in order to maintain the balance is 1.8 m
