Final answer:
The brake requirement exemptions for trailers vary by jurisdiction and therefore cannot be definitively answered without specific local law references. For the physics problems, the resisting force is calculated using Newton's Second Law and the hitch force with the given percentage of resistance faced by the trailer. 2) 4,500 pounds
Step-by-step explanation:
The question you're asking about trailers, semitrailers, and pole trailers is related to traffic laws and vehicle regulations, which can vary based on jurisdiction. To answer such questions accurately, it's best to refer to the specific state's Department of Motor Vehicles (DMV) or equivalent authority for the most up-to-date information. Generally, in many places, trailers with a gross weight of 3,000 pounds or less are often exempt from brake requirements; however, options 1) 4,000 pounds, 2) 4,500 pounds, and 3) 5,000 pounds suggest this could be a specific local regulation. Without the correct jurisdiction, providing an accurate answer is challenging.
Regarding the physics problem you presented, part (a) can be solved using Newton's second law of motion, F = ma, where F is the force applied, m is the mass of the objects, and a is the acceleration. Since the combined mass of the car and trailer is 1800 kg (1100 kg for the car and 700 kg for the trailer), and the car applies a force of 1900 N to produce an acceleration of 0.550 m/s², we can calculate the total resisting force. The total force required to accelerate the car and trailer can be found by multiplying the total mass by the acceleration, 1800 kg × 0.550 m/s² = 990 N. Since the car is exerting a 1900-N force to achieve this, the difference of 910 N can be considered as the resisting force.
For part (b), if 80% of the resisting force is on the boat and trailer, then that is 80% of 910 N, which is 728 N. This would be the force in the hitch between the car and the trailer.
Lastly, when a trailer on a highway is bouncing up and down slowly, it is more likely nearly empty. A heavily loaded trailer would have less pronounced bounces due to the greater mass, which dampens oscillation, whereas an empty or lightly loaded trailer would oscillate more noticeably due to having less mass to counteract the springs' push.