Answer:
a.
b.
Explanation:
We are given that




a.We have to find the angle


b. We have to find the speed 
According to law of conservation of momentum



The distance covered by the acorn is 3.136 m.
<u>Explanation:</u>
The time taken for the acorn to hit the ground is 0.8 s. As it is a free fall, the acorn will be completely under the influence of gravity. So the acceleration will be acceleration due to gravity.
Then using the second law of equation,

Since the initial velocity and time is zero, then the time taken to reach the ground is stated as 0.8 s, so

So the distance covered by the acorn is 3.136 m.
Answer:
Explanation:
velocity of sound in air at 20⁰C is 343 m /s
velocity of sound in water at 20⁰C is 1481 m /s
The wavelength of the sound is 2.86 m in the air so its frequency
= 343 / 2.86 = 119.93 .
This frequency of 119.93 will remain unchanged in water .
wavelength in water = velocity in water / frequency
= 1481 / 119.93
= 12. 35 m .
Things are rubbed against each other
Answer:
Is there a multiple choice or select all that apply? I would say Potassium (K) or Sodium (Na)
Explanation: