The frequency of the wave is 6800 Hz
<u>Explanation:</u>
Given:
Wave number, n = 20
Speed of light, v = 340 m/s
Frequency, f = ?
we know:
wave number = 

Therefore, the frequency of the wave is 6800 Hz
Answer:
B) the change in momentum
Explanation:
Impulse is defined as the product between the force exerted on an object (F) and the contact time (
)

Using Newton's second law (F = ma), we can rewrite the force as product of mass (m) and acceleration (a):

However, the acceleration is the ratio between the change in velocity (
) and the contact time (
):
, so the previous equation becomes

And by simplifying
,

which corresponds to the change in momentum of the object.
Answer:
This question can be answered by using conversation of energy.



Explanation:
Note that we take
because we are looking for the minimum initial speed for the penguin to reach the top of the second hill. Any other speed more than this will already be enough for him.
Answer: I am pretty sure the answer is B
Explanation: If not sorry bro.