Physics MCQs
Topic Notes: Physics
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
1
Which fundamental conservation principle governs the propulsion of a rocket?
Answer:
Conservation of momentum
A rocket operates based on Newton's third law and the law of conservation of linear momentum. As the rocket expels exhaust gases at high velocity in the backward direction, the system gains an equal and opposite momentum in the forward direction, causing the rocket to accelerate.
2
If momentum (p) and velocity (v) are given, the formula used to find mass (m) will be:
Answer:
$$\frac{p}{v}$$
Source answer preserved: option B ($$\frac{p}{v}$$). AI attempted to change protected answer data (option_b, option_c), so this item is flagged for manual review before study use.
3
How is linear momentum mathematically defined in classical mechanics?
Answer:
Mass and velocity
Linear momentum is a vector quantity defined as the product of an object's mass and its velocity (p = mv). It represents the quantity of motion an object possesses. Because it is the product of a scalar (mass) and a vector (velocity), momentum is itself a vector quantity, sharing the same direction as the velocity vector. It is a fundamental concept in the study of collisions and dynamics.
4
The impulse applied to a particle by a force over a specific time interval is equivalent to the change in which physical quantity?
Answer:
momentum
According to the impulse-momentum theorem, the impulse exerted on an object is equal to the change in its linear momentum. Impulse is defined as the integral of force over time, which mathematically results in the change in momentum (mass times change in velocity).
5
Calculate the magnitude of a constant force applied to an 8 kg object for 3 seconds, resulting in a velocity change from 4 m/s to 6 m/s.
Answer:
5.33 N
Using the impulse-momentum theorem or Newton's second law, acceleration a = (v_final - v_initial) / t. Here, a = (6 - 4) / 3 = 2 / 3 = 0.666... m/s^2. The force F = m * a = 8 kg * 0.666... m/s^2 = 5.333... N. Thus, the magnitude of the applied force is approximately 5.33 N.
6
What is the physical quantity defined as the product of an object's mass and its velocity?
Answer:
momentum
Momentum is a vector quantity defined as the product of an object's mass (m) and its velocity (v), expressed by the formula p = mv. It represents the quantity of motion an object possesses and is a fundamental concept in classical mechanics, particularly when analyzing collisions and interactions between bodies.
7
What is the physical term for the product of an object's mass and its velocity?
Answer:
momentum
In classical mechanics, linear momentum is defined as the product of the mass of a particle and its velocity. It is a vector quantity that represents the quantity of motion an object possesses.
8
If two objects of different masses, starting from rest, are subjected to the same force for an identical duration, what physical quantity will they both acquire?
Answer:
Momentum
According to the impulse-momentum theorem, the change in momentum of an object is equal to the impulse applied to it, defined as the product of force and time. Since both objects experience the same force for the same time, they receive the same impulse and thus acquire identical final momentum.
9
When a shell explodes into multiple fragments moving in various directions, which physical quantity is conserved?
Answer:
momentum
In an explosion, internal forces dominate, and the net external force on the system is negligible. According to the law of conservation of linear momentum, the total momentum of the system remains constant before and after the explosion, regardless of the directions in which the fragments travel.
10
Calculate the linear momentum of an object with a mass of 8 kg traveling at a velocity of 4 m/s.
Answer:
32
Linear momentum is defined as the product of an object's mass and its velocity (p = mv). Given a mass of 8 kg and a velocity of 4 m/s, the calculation is 8 kg * 4 m/s = 32 kg·m/s.