Answer: 81.619 kJ
Explanation:
Given
Mass of roller coaster is 
It reaches the steepest hill with speed of 
Hill to bottom is 51 m long with inclination of 
Height of the hill is 
Conserving energy to get kinetic energy at bottom
Energy at top=Energy at bottom

Yes it is valid all the times under the consideration of acceleration due to gravity .it is not valid on space where there is no influence of gravity
What exactly do u want me to know step by step with me plz I am a slow person
Answer:
At light intensity I = 3, is P a maximum
Explanation:
Given:

now differentiating the above equation with respect to Intensity 'I' we get

or

or

or

Now for the maxima 
thus,

or

or

or

or
I = 3
thus, <u>for the value of intensity I = 3, the P is maximum</u>
at I = 3

or

or

The speed of the wave in the string is 83.4 m/s
Explanation:
For a standing wave in a string, the speed of the wave is given by the equation:

where
L is the length of the string
T is the tension in the string
m is the mass of the string
In this problem, we have:
L = 0.72 m
m = 4.2 g = 0.0042 kg
T = 84.1 N
Solving the equation, we find the speed of the wave:

Learn more about waves:
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