Free NTN Mechanical Comprehension Questions and Answers 1 — Questions and Answers
Question 1: Which principle explains why a larger gear rotates slower than a smaller gear when they are meshed together?
- Gear ratio (Correct answer)
- Conservation of energy
- Newton's third law
- Friction
Correct answer: Gear ratio
The gear ratio explains the relationship between the rotational speeds and torques of meshed gears. When a smaller gear drives a larger gear, the larger gear has more teeth and must rotate fewer times to complete a revolution, resulting in a slower rotational speed. Conversely, this setup increases the torque, demonstrating the mechanical advantage provided by the gear system.
Question 2: What is the purpose of a pulley system in mechanical operations?
- To increase friction
- To change the direction of a force and reduce the amount of force needed to lift a load (Correct answer)
- To generate heat
- To prevent motion
Correct answer: To change the direction of a force and reduce the amount of force needed to lift a load
The primary purpose of a pulley system in mechanical operations is to change the direction of an applied force and to provide mechanical advantage, thereby reducing the amount of force needed to lift a load. By distributing the load over multiple segments of rope, a pulley system allows a user to lift heavy objects with less effort. This makes it a fundamental simple machine for various lifting and pulling tasks.
Question 3: In a hydraulic system, if the force applied on the smaller piston is increased, what happens to the pressure in the system?
- It decreases
- It remains the same
- It increases (Correct answer)
- It fluctuates
Correct answer: It increases
In a hydraulic system, pressure is transmitted equally throughout an enclosed fluid, as described by Pascal's principle. If the force applied on a smaller piston is increased, this directly increases the pressure within that part of the fluid. Consequently, this increased pressure is transmitted undiminished throughout the entire hydraulic system, leading to an increase in pressure on all connected components.
Question 4: Which law explains the mechanical advantage gained by using a lever?
- Boyle's law
- Bernoulli's principle
- Law of the lever (Archimedes' principle) (Correct answer)
- Law of conservation of mass
Correct answer: Law of the lever (Archimedes' principle)
The mechanical advantage gained by using a lever is explained by the Law of the Lever, often attributed to Archimedes. This principle states that for a lever to be in equilibrium, the product of the force on one side and its distance from the fulcrum (torque) must equal the product of the force on the other side and its distance. By adjusting the position of the fulcrum, a smaller input force can be used to move a larger load, demonstrating the lever's ability to multiply force.
Question 5: What type of motion does a cam convert?
- Rotational motion to linear motion (Correct answer)
- Linear motion to rotational motion
- Rotational motion to fluid motion
- Linear motion to sound waves
Correct answer: Rotational motion to linear motion
A cam is a mechanical component specifically designed to convert rotational motion into reciprocating, or linear, motion. As the cam rotates, its uniquely shaped profile interacts with a follower, causing the follower to move back and forth or up and down in a predetermined pattern. This conversion is a fundamental principle used in many machines, from internal combustion engines to automated manufacturing equipment.
Free NTN Mechanical Comprehension Questions and Answers 1
Which principle explains why a larger gear rotates slower than a smaller gear when they are meshed together?