Answer:

Explanation:
When we shoot the dart upwards the time taken by the dart to go straight up and again come back is given as

here we can say


put t = 4.6 s then we have

Now in order to find the maximum range we can say

so in order to have maximum range we can say




Answer:
Explanation:
Let s be displacement from equilibrium position . Restoring force
m d²s / dt² = - k s
d²s / dt² = - k /m s
Put k /m = ω
d²s / dt² + ω² s = 0
The solution of this differential equation
= s = A cosωt
Now when t = 0 , s = 2 cm
A = 2 cm
Putting the values we have
2 = A cos 0
A = 2 cm
s ( t) = 2 cos ωt
The megaphone is cupping the area around her mouth and it is like with your hands, if you cover around them the noise will be louder. It is because it is hollow and there isn't anything to block the noise through the megaphone.