An object with a mass of 20kg changes position as a function of time according to the expression r = 4t ^ 2i + 5j, where r is expressed in meters and t in seconds. a) What is the expression of velocity as a function of time of the object? b) What is the expression of acceleration as a function of time of the object? c) What is the position, velocity and acceleration of the object at t = 3s? d) What is the force of the object and in what direction is it heading (east, north, west or south)?

to be honest as much as i would love to answer this. i feel as if something's missing. just saying.

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day

lol

explanation:

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.