Momentum is conserved in a collision. Momentum is mass*velocity, so you can find your answer by calculating initial and final momentums and setting them equal to each other.
15kg * 3.50 m/s + 9kg * 2.35 m/s = 73.65 kg m/s
73.65 = 9 * 2.8 + 15x
solve for x
x= 3.23
The final velocity is 3.23 m/s
        
             
        
        
        
Ike is at the beach watching the waves in the ocean. Ike notices that some of the waves are short. Other waves are very tall and come up high above the water. Two waves that are different heights because They have different amplitudes.
Answer: Option (D) is correct
Explanation:
The different heights of the waves are due to their different amplitudes. The Amplitude of a particular wave depends upon the amount of energy being carried by waves. It the waves carry more energy than their amplitude will be higher.
But if energy carried by a wave is less than the wave will have a low amplitude. The Amplitude shows the distance covered from the rest position to peak position. 
 
 
        
             
        
        
        
Neptune was named after the Roman god of the sea and it is the last known of the planets
        
             
        
        
        
Answer:
The distance from the Sun to Neptune is 29,41 AU.
Explanation:
We know, from the sentence, that the orbit of Neptune has an average diameter around 8.80*10⁹km. 
 
Now, we can calculate the radius of this orbit, which is equivalent to the distance from thsi planet to the Sun. Let's recall tha the radius is the half of the diameter.

Ok, we know that 1.496*10¹¹m is an AU, therefore we have:

Finally, the distance R is 29,41 AU. 
I hope it helps you! :)
 
        
             
        
        
        
Answer:
The height reached by the material on Earth is 91 km. 
Explanation:
Given that,
Mass 
Radius = 1821 km
Height 
Suppose we need to find that how high would this material go on earth if it were ejected with the same speed as on Io?
We need to calculate the acceleration due to gravity on Io
Using formula of gravity

Put the value into the formula


Let  v be the speed at which the material is ejected.
We need to calculate the height
Using the formula of height

Using ratio of height of earth and height of Io


Put the value into the formula





Hence, The height reached by the material on Earth is 91 km.