The force of 75 n must overcome in order to get the truck to start moving. what type of friction must be overcome?

Static Friction.

Explanation:

Friction is the force that resists the relative motion between the surfaces sliding against each other.

Static friction is friction between objects that are not in relative motion with each other.

The coefficient of static friction, typically denoted as  μs,

Static friction arises due to surface roughness( relative term)

The static friction force can be overcome by an applied  maximum force

F max =  μs x N

N= normal force

Any force smaller than F max attempting to slide one surface over the other is opposed by a frictional force of equal magnitude and opposite direction.

Any force larger than F max overcomes the force of static friction and causes sliding to occur.

This maximum force is sometimes called the limiting value also. Here that value is 75 N.

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.