Q191. The mechanical advantage of a simple machine is defined as the ratio of:
Basics of Everyday Science: RAS Prelims MCQs
200 RAS Prelims MCQs on the basics of everyday science test the scientific method, the laws of motion, chemical bonding and the cell theory. The questions use daily-life examples, such as the recoil of a gun and the orbit of a satellite, and the explanations give the principle behind each example so that you can reason out similar questions.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
Showing 191–200 of 200 questions
Q192. A pair of scissors is an example of a:
Explanation
A pair of scissors is a classic example of a Class 1 lever. In this arrangement, the fulcrum or pivot point is located between the effort applied by the fingers at the handles and the load, which is the material being cut by the blades. This configuration allows for a change in the direction of force and can be designed to provide a mechanical advantage.
Q193. In a Class 2 lever, such as a wheelbarrow or a nutcracker, the positions are arranged as:
Explanation
In a Class 2 lever, the load is positioned between the fulcrum and the effort. Common examples include wheelbarrows and nutcrackers. Because the effort arm is always longer than the load arm in this configuration, Class 2 levers always provide a mechanical advantage greater than one. This allows the user to lift heavy objects with significantly less force than would be required.
Q194. Consider the following statements about simple machines:
I. They can multiply force.
II. They can multiply speed or distance.
III. They can change the direction of an applied force.
IV. They can multiply work, outputting more energy than is put in.
V. An inclined plane is a type of simple machine.
Which of the above statement(s) is/are incorrect?
I. They can multiply force.
II. They can multiply speed or distance.
III. They can change the direction of an applied force.
IV. They can multiply work, outputting more energy than is put in.
V. An inclined plane is a type of simple machine.
Which of the above statement(s) is/are incorrect?
Explanation
Simple machines are designed to make work easier by multiplying force, increasing speed, or changing the direction of an applied force. However, they cannot multiply work or energy. According to the law of conservation of energy, the output work can never exceed the input work. In fact, due to friction, the useful work output is always slightly less than total energy.
Q195. In a Class 3 lever, the mechanical advantage is always:
Explanation
In a Class 3 lever, the effort is applied between the fulcrum and the load. Because the effort arm is always shorter than the load arm, the mechanical advantage is consistently less than one. While these machines require more force than the load itself, they are useful because they multiply the distance or speed at which the load moves, as seen in tweezers.
Q196. A single fixed pulley offers a mechanical advantage of approximately 1. What is its primary practical purpose?
Explanation
A single fixed pulley has a mechanical advantage of approximately one, meaning the effort required is equal to the load. While it doesn’t multiply force, its primary practical advantage is changing the direction of the applied effort. This allows a person to pull downward using their body weight to lift a load upward, which is often much easier than lifting directly.
Q197. Match the simple machines in List I with their corresponding everyday examples in List II.
| Simple Machine | Everyday Example |
|---|---|
| A. Inclined plane | i. Axe blade |
| B. Wedge | ii. Doorknob |
| C. Screw | iii. Wheelchair ramp |
| D. Wheel and axle | iv. Spiral staircase |
Explanation
Simple machines are found in many common objects. A wheelchair ramp is a practical application of an inclined plane. An axe blade functions as a wedge to split wood. A spiral staircase acts as a screw wrapped around a central pillar. A doorknob is a classic example of a wheel and axle system. These devices all serve to manipulate applied force.
Q198. A screw can be fundamentally described as which type of simple machine wrapped around a central cylinder?
Explanation
A screw is fundamentally an inclined plane that has been wrapped around a central cylinder or shaft in a spiral pattern. The threads of the screw act as the sloping surface. This design converts rotational motion and torque into linear force and displacement. By spreading the effort over a longer distance along the threads, a screw provides a high mechanical advantage.
Q199. The efficiency of a practical simple machine is always less than 100% primarily due to:
Explanation
The efficiency of any real-world simple machine is always less than one hundred percent. This is primarily because some of the input energy is always converted into non-useful forms, such as heat and sound, due to friction between moving parts. While lubrication can reduce these losses, friction can never be entirely eliminated, ensuring that output work is always less than input work.
Q200. Match the machine terms in List I with their corresponding definitions in List II.
| Machine Term | Definition |
|---|---|
| A. Fulcrum | i. The fixed point around which a lever pivots |
| B. Load | ii. The resistance force to be overcome |
| C. Effort | iii. The force applied to the machine |
| D. Velocity Ratio | iv. Ratio of distance moved by effort to distance moved by load |
Explanation
Understanding simple machines requires defining key terms. The fulcrum is the fixed pivot point of a lever. The load represents the weight or resistance to be moved, while the effort is the force applied by the user. The velocity ratio is the distance moved by the effort divided by the distance moved by the load. Together, these terms describe mechanical performance.Answer key for these questions
| Q | Correct answer |
|---|---|
| 191 | (a) Load force to effort force |
| 192 | (b) Class 1 lever |
| 193 | (b) Load is between the Fulcrum and the Effort |
| 194 | (c) IV only |
| 195 | (b) Less than 1 |
| 196 | (d) To change the direction of the applied effort |
| 197 | (a) A-iii, B-i, C-iv, D-ii |
| 198 | (b) An inclined plane |
| 199 | (d) Friction between moving parts |
| 200 | (a) A-i, B-ii, C-iii, D-iv |
Key facts from Basics of Everyday Science
- Inductive reasoning draws a general conclusion from specific observations; a control variable is kept constant in an experiment; communicating the results is the last step of the scientific method.
- Newton’s second law relates force, mass and acceleration; the recoil of a gun illustrates the third law.
- Momentum is the product of mass and velocity; impulse is equal to the change in momentum.
- A satellite in uniform circular orbit is held by the centripetal force provided by gravity.
- Water (H₂O) and N₂ show covalent bonding; sodium chloride, MgO and CaF₂ are ionic.
- The classical cell theory does not say that all cells have a true nucleus.
Frequently asked questions
How many RAS Prelims practice MCQs are there on Basics of Everyday Science?
This page has 200 practice MCQs on Basics of Everyday Science (Science and Technology). Each has the correct answer, and most have an explanation.
What is the product of mass and velocity called?
Momentum. Newton’s second law says that the rate of change of momentum is equal to the force applied, and impulse is equal to the change in momentum of a body.
Which law explains the recoil of a gun?
Newton’s third law of motion. The gun pushes the bullet forward, and the bullet pushes the gun back with an equal and opposite force, which is felt as recoil.
What holds a satellite in a circular orbit?
The centripetal force provided by gravity. The Earth’s pull keeps changing the direction of the satellite’s velocity so that it moves in a circle and does not fly off in a straight line.