Answer:
Inertia! I hope this helps!
Answer:

Explanation:
Given:
width of the wire, 
thickness of the flat wire, 
length of the wire, 
voltage across the wire, 
current through the wire, 
Now the net resistance of the wire:
using ohm's law



We have the relation between the resistivity and the resistance as:

where:
a = cross sectional area of the wire
resistivity of the wire material


Answer:
The height is "89.61 m". A further explanation is given below.
Explanation:
According to the question,
Mass of rocket,
m = 5 kg
Time,
t = 4.6 s
Initial speed of rod
u = o m/s
Final speed,
v = 39 m/s
drag,
= 60 N
So,
⇒ acceleration, 


⇒ 



Now,
The thrust will be:
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
The height will be:
⇒ 



100m ÷ 50s = 2m/s
Just some simple divison.
Since the track is friction less, block’s kinetic energy at the bottom of the track is equal to its potential energy at the top of the track.
PE = 81 * 9.8 * 3.8 = 3016.44 J
Work = 1/2 * 1888 * d^2
PE = Kinetic energy at the base.
1/2 * 1888 * d^2 = 3016.44
d = 1.78 approx 1.8
F = Ke = 1888 * 1.8 = 3398.4N