Answer:
Explanation:
Velocity of sound in air at 20 degree = 343 m/s
Velocity of sound in water at 20 degree = 1470 m/s
Time taken in to and fro movement in air
=( 2 x 10) / 343 = 0.0583 s
Rest of the time is
.171 - .0583 = .1127 s
This time is taken to cover distance in water. If d be the depth of lake
2d / velocity = time taken
2 d / 1470 = .1127
d = 82.83 m
Speed of Ferry is towards North with magnitude 6.2 m/s
Here if we assume that North direction is along Y axis and East is along X axis then we can say

Now a person walk on ferry with speed 1.5 m/s towards east with respect to Ferry
so it is given as

also by the concept of relative motion we know that

now plug in all values in it


now if we need to find the speed of the person then we need to find its magnitude
so it is given as


Answer:
b
Explanation:
they both have a neutral charge so they couldn't be positive or negative since that wouldn't come from anywhere
Viscosity of liquids is essentially the 'thickness' of the liquid. For instance, honey and water have different viscosities. Honey has a higher one and therefore, liquids with high viscosity do not flow as well as liquids with low viscosity (water).