Good are free zones bad is car pollution ext.
Answer:
60m
Explanation:
According to one of the equation of motions, v² = u²+2as where;
S is the distance
u is the initial velocity
v is the final velocity
a is the acceleration
Since the arrow is shot upwards, the body will experience a negative acceleration due to gravity i.e a = -g
Therefore our equation will become;
v² = u² - 2gS
Given u = 40m/s, g = 10m/s², S = 75m
Substituting to get the final velocity of the arrow we will have;
v² = 40²-2(10)(75)
v² = 1600 - 1500
v² = 100
v = √100
v = 10m/s
Total distance traveled is speed of the object × time taken
Total distance traveled = 10 × 6
= 60m
The arrow has therefore traveled 60m after 6seconds
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