Answer:
3.7 km/h
Explanation:
Let's call v the proper speed of the boat and v' the speed of the water in the river.
When the boat travels in the direction of the current, the speed of the boat is:
v + v'
And it covers 50 km in 3 h, so we can write
(1)
When the boat travels in the opposite direction, the speed of the boat is
v - v'
And it covers 50 km in 5.4 h, so
(2)
So we have a system of two equations: by solving them simultaneously, we find the value of v and v':

Subtracting the second equation from the first one we get:

So, the speed of the water is 3.7 km/h.
Answer:
The horizontal distance covered by the firework will be 
Explanation:
Let acceleration due to gravity on the planet be g, initial velocity of the firework be u and angle made with the horizontal be ∅.
writing equation of motion in vertical direction:


and 
therefore 
writing equation of motion in horizontal direction:


therefore the equation becomes 
therefore horizontal distance traveled =
Answer:
KE = KE (incidental) - KE of emitted photons
or KE = h * f - Wf
So h * f = KE + Wf = 1.2 + 1.88 = 3.08 incident energy
If you double the frequency then h * f = 6.16
KE = 6.16 - 1.2 = 4.96 eV
Explanation:
Rhythm, Harmony, Timbre, Dynamics, Texture, and Form
<span>i believe the answer is
D. Wool is an excellent thermal insulator because heat flows through it very slowly.</span>