Answer:
18.6012339739 A
Explanation:
= Vacuum permeability = 
L = Length of wire = 55 cm
N = Number of turns = 4000
I = Current
Magnetic field is given by

The current necessary to produce this field is 18.6012339739 A
A horizontal line on a speed/time graph means a constant speed.
C.
remember
reactants ----> products
Kinetic energy is the energy possessed by an object on motion. it is expressed as follows:
KE = 0.5mv^2
where m is the mass and v is the velocity of the object. We calculate as follows:
KE = 0.5mv^2
1.1x10^9 J = 0.5(8.0x10^4 kg) v^2
v = 165.83 m/s
According to my examination I have confirmed that I do NOT repeat do NOT know this .