<span>The zero reference position should be the position the system has the least potential energy. As an object falls, its potential energy is converted into kinetic energy.
Gravity's ability to do work (potential energy) reaches zero when it hits the ground and stops falling, hence the ground is the most common zero reference position.</span>
ANSWER

EXPLANATION
Parameters given:
Mass of car, mc = 1103 kg
Mass of truck, mt = 4919 kg
Initial velocity of car, uc = 18 m/s
Inital velocity of truck = 0 m/s
To solve this problem, we have to apply the law of conservation of momentum, which states that the total momentum of a system is constant.
This implies that:

Since the car and the truck stick together after the collision, they will have the same final velocity.
Hence:

Substitute the given values and solve for v (final velocity):

That is the final velocity of the two-vehicle mass.
<span>s=2.7 centimeters = 0.027 meters
t=3.9 milliseconds = 0.0039 seconds
s=(1/2)a*t^2
so
a=(2.7*2)/(0.0039)^2
= 355,029.58 m/s^2
a=355,029.58 m/s^2 = 355.02958 km / s^2</span>
Answer:
Police officer
Explanation:
Because police officers wants to gather information on what happens and question people to know everything. That is what Derick is doing