Answer:

Explanation:
Gravity on the surface of planet is given as

as we know that


now gravity on the planet is

so we have

now we know that

so we will say



Gravitational acceleration is approx 9.8 m/s
Time is 7s
a=9.8 m/s
t=7s
a = d/t^2
therefore:
d = a * t^2
d = 9.8 * 7^2
d = 9.8 * 49
d = 480.2 [m]
Answer:
About 2.19 seconds
Explanation:

Since the ball is dropped from rest, there is no initial velocity, and you can write the following equation:

Hope this helps!
Answer:

Explanation:
Natural length of the string is given as

length of the string while block is hanging on it

extension in length is given as

now we have strain in the string is given as



similarly we will have cross-sectional area of the string is given as

now the stress in the string is given as




Now Young's Modulus is given as


