First, let's list everything we have...
a = 1.83 m/s^2
F = 1870 N (converted from kN to N)
vi = 0 m/s (it says started from rest, therefore velocity starts at 0)
t = 16 s
1). "Force acting on the car" is a bit ambiguous because there are many forces. But I'm going to assume that they are looking for just a basic implementation of force equation:

where:
F = force
m = mass
a = acceleration
2). I recommend memorizing your equations of motion, because once you know them this part is also just as easy:

where:
vf = final velocity
vi = initial velocity
a = acceleration
t = time
Density = (mass) / (volume)
Density = (20 g) / (5 cm³)
<em>Density = 4 g/cm³</em> .
The density of the substance is greater than the density of water. A lump of the substance <em>will sink in water</em>, <u>unless</u> the lump is formed into a shape that displaces 20 cm³ of water or more, such as a tiny boat shape.
Answer:
Displacement is the shortest distance from your initial position to your final position. Therefore, displacement is a measurement of distance and not an "end-point."