Answer:
The speed of ejection is 
Solution:
As per the question:
Magnetic field density, B = 0.4 T
Density of the material in the sunspot, 
Now,
To calculate the speed of ejection of the material, v:
The magnetic field energy density is given by:

This energy density equals the kinetic energy supplied by the field.
Thus


where
m = mass of the sunspot in
= 


Answer with Explanation:
We are given that
Mass of rock=m
Maximum height=h
a.At maximum height, velocity,v=0
We know that



Height,h=h/4
Again,


Where 
b.When height,h=3h/4




Answer:
a)
b)
Explanation:
Given that
v(t) = 5 t i + t² j - 2 t³ k
We know that acceleration a is given as



Therefore the acceleration function a will be

The acceleration at t = 2 s
a= 5 i + 2 x 2 j - 6 x 2² k m/s²
a=5 i + 4 j -24 k m/s²
The magnitude of the acceleration will be

a= 24.83 m/s²
The direction of the acceleration a is given as

a)
b)