A roller coaster car starts from the rest from a first summit, descends a vertical distance of 45 meters and then climbs a second summit, reaching the top with a speed of 15m / s. How high is the second summit? Do not consider friction
Answer:
The block's mass should be 
Explanation:
Given:
Cart with mass 
From the conservation of energy before mass is added,

Where
amplitude of spring mass system,
spring constant

Now new mass
is added to the system,


Here, given in question frequency is reduced to half so we can write,

Where
frequency of system before mass is added,
frequency of system after mass is added.




Therefore, the block's mass should be 
The ration of the rms speed of 235uf6 to that of 238uf6 is 1.004.
The molecular mass of 235uf6 is 349, while that of 238uf6 is 352.
The rms speed is calculated as
v=√(3RT/m)
Thus the ratio rms speed of 235uf6 to 238uf6 is calculated as
r=√(352/349)=1.004
If you put a penny in each light spot the penny that the light is shining on will recive the most energy.