Short Q/A Dynamics – I - Students Free Notes

Short Q/A Dynamics – I

Define an isolated system. State the law of conservation of linear momentum. Explain with an example. short answer

Isolated System: An isolated system is a system in which no external forces act on the objects within the system. In other words, the total external force on the system is zero. Law of Conservation of Linear Momentum: The law of conservation of linear momentum states that the total linear momentum of an isolated system … Read more

State and prove Newton’s second law of motion in terms of momentum.

Newton’s Second Law of Motion in Terms of Momentum: Newton’s Second Law of Motion can be expressed in terms of momentum as follows: Statement: The rate of change of momentum of a body is directly proportional to the net external force acting on it and occurs in the direction of the force. Mathematically, the law … Read more

Justify and illustrate the use of electronic balances to measure mass.

Electronic balances measure mass, not weight, because they function based on internal calibration using standard masses. They operate using electromagnetic force compensation, where an electromagnetic field counteracts the gravitational force on the object, providing a precise mass measurement regardless of location. This makes electronic balances more accurate than spring balances, which depend on gravitational variations. … Read more

When Ronaldo kicks a ball, at the highest point of the ball’s trajectory, both Earth and the ball attract each other with the same magnitude of force. Why does the ball move toward Earth and not the Earth toward the ball?

According to Newton’s third law, both Earth and the ball experience equal gravitational force. However, Earth has a much larger mass, so its acceleration is negligible, whereas the ball accelerates downward due to Earth’s gravity. Related Questions: When a motorcyclist hits a stationary car, he may fly off the motorcycle, and the driver in the … Read more

How would you use Newton’s third law of motion and the law of conservation of momentum to explain the motion of a rocket?

Newton’s third law states that for every action, there is an equal and opposite reaction. The rocket expels gases downward with great force (action), and in reaction, the rocket moves upward. The law of conservation of momentum ensures that the total momentum of the system remains constant, causing continuous acceleration of the rocket. Related Questions: … Read more

A man slips on an oily floor; he wants to move out of this area. He is alone. He throws his bag to move out of this slippery area. Why is it so?

When he throws the bag, an equal and opposite reaction force pushes him in the opposite direction, helping him move out of the slippery area. This is an application of Newton’s third law of motion. Related Questions: When a motorcyclist hits a stationary car, he may fly off the motorcycle, and the driver in the … Read more

Action and reaction are equal but opposite in direction. These forces always act in pairs. Do they balance each other? Can bodies move under an action-reaction pair?

Action and reaction forces act on different bodies, so they do not cancel each other out. Since they act on separate objects, they can cause motion, as seen when a swimmer pushes water backward and moves forward. Related Questions: When a motorcyclist hits a stationary car, he may fly off the motorcycle, and the driver … Read more