(a) The length of the train is 54.6 m
(b)  The braking distance of the road train is 194.44 m
The given parameters:
acceleration of the car, a = 3.7 m/s²
initial velocity of the car, u = 30 m/s
final velocity of the car, v = 130 km/h = 36.11 m/s
To find:
The length of the train is the distance travelled by the car 
The distance traveled by the car is calculated as:

Thus, the length of the train is 54.6 m
(b) The braking distance of a road train travelling at 25 m s⁻¹

Thus, the braking distance of the road train is 194.44 m
Learn more here: brainly.com/question/19572178
 
        
             
        
        
        
Work = Force x Distance
47.2J = 23.3N x d
d = 47.2/23.3
d = 2.0258 m
hope this helps :P 
        
             
        
        
        
Explanation:
Contact force is any force that requires contact.  An object that exerts a force on another object by touching it is exerting a contact force.  Examples of contact force are friction and normal force.
Examples of a non-contact force are gravity and magnetism.
 
        
                    
             
        
        
        
Answer:
+ 14
Explanation:
18 protons make a positive 18 charge (+18)
4 electrons make a negative 4 charge (-4)
both combined give + 18 - 4 = + 14
The four neutrons don't carry net charge, so the addition of the electrons doesn' affect the net charge found above which still gives + 14.