Answer: Capacitor
Explanation:
Given the following ;
At time, t = T/4 ; I = 0
At time, t = T/2 ; I = - Imax
Where T = period
We can confirm what the unknown element is by using the relation, such that the parameters satisfy the stated condition ;
Recall;
I = Iosin(wt + π/2) [for CAPACITOR]
w = 2π/T
At t = T/4
I = Iosin(2π/T(T/4) + π/2)
I = Iosin(π/2 + π/2)
I = Iosin(0)
I = 0
At t = T/2
I = Iosin(2π/T(T/2) + π/2)
I = Iosin(π + π/2)
I = Iosin(0)
I = Iosin(3π/2)
I = Iosin(540/2)
I = Iosin(270)
I = -Io
Note : Io = Imax
Both conditions are met, Hence, the unknown element is a CAPACITOR.
We can solve this problem using the force equation.
Force = Mass * Acceleration
2kg * 4m/s = 8 N
The net force required to keep the object moving at this speed and in this direction is 8 N.
Answer:
i) Mr. Dunn arrives to home first.
ii) 3 min
Explanation:
i. To find who arrives first to home you calculate the time, by using the following formula:

x: distance
v: velocity
Mr. Dunn:

Mrs. Dunn:

Hence, Mr. Dunn arrives to home first.
ii. To calculate the difference in minutes, you convert hours to minutes:

the difference between the times is 3min
El sol le da luz a la luna entonces la luna brilla