Answer:
7) 
8) 
9) 
10) 
Explanation:
For the problems 7, 8 and 9 we just apply the definition of acceleration, since no more information is given, which is:

So for each problem we will have:
7) 
8) 
9) 
For the problem 10, we use the equation of velocity in accelerated motion:

Since the ball starts from rest and the acceleration is that of gravity (we take the downward direction positive), we have:

There are already 2 givens, hence we can do direct substitution to get the answer. To make the process simpler, derive the distance formula from the Work formula.
Work = Force x Distance
Distance =

Work is 450J while the force is 150N hot tub
To get the proper units, get the equivalent of Joule to eliminate newton. A joule Is equal to 1 N-m
Distance =

Distance = 3m
Hence, the hot tub is lifted 3 meters.
Answer:
The impedance of the inductor is ω L:
This is in parallel wth R giving a resistance of the parallel combination:
1 / Rp = 1 / ω L + 1 / R
Rp = (ω L * R) / (ω L + R) for the impedance of the parallel combination
Total resistance (impedance) Rt = Rp + R2 = Z
One can use the term impedance to show that the resulting current is not in phase with the resulting voltage
phase angle φ - cos φ = ω L / Rt
V = I Z shows the relation of voltage and urrent