Answer:
both are correct .... ....
The ratio of the speed of light v in a medium to the speed of light in a vacuum c is called its Refractive Index n
v/c=n
Different substances have different Refractive Indices (plural of Index). Values are always bigger than 1.
Refractive index of water is 1.33
Refractive index of glass is about 1.4
So in calculating this one its is really hard to explain how i get it on solve it but you must consider this factors that i give in getting the answer. First is the distance cover by the ball when it is hit by the club, Second is you must estimate both of those data when it is in the moon and in the earth whre the gravity of the earth is 9.8m/s^2 so by calculating the Gravity of the moon or gMoon is equal 1.74m/s^2
Part a)
Centripetal acceleration is defined as

now here we know that


m = 3 kg
now from above formula we have


Part b)
Maximum possible tension in the string is given as

now by force equation we have



now again by above formula



Answer:
67.5
Explanation:
The plane accelerates at 2.7m/s,^2
Time is 25 seconds
The velocity can be calculated as follows
= 25×2.7
= 67.5
Hence the speed f the plane is 67.5