Laws Of Motions (VSAQs)
Physics-1 | 5. Laws of Motion – VSAQs:
Welcome to VSAQs in Chapter 5: Laws of Motion. This page includes the most significant FAQs for Very Short Answer Questions. Each answer is provided in simple English and follows the exam format. This helps you concentrate on essential concepts and aim for top marks in your final exams.
VSAQ-1 : A horse has to exert a greater force during the start of the motion than later. Explain.
A horse exerts a greater force at the start of its motion due to inertia. Inertia is an object’s tendency to remain at rest or in uniform motion. When a horse starts from rest, it must overcome this initial inertia, requiring a higher force. As it gains momentum and begins moving, its inertia decreases, allowing it to maintain motion with less force. Thus, the force required at the start of motion is higher than when it is already moving.
VSAQ-2 : What happens to the coefficient of friction if the weight of the body is doubled?
If the weight of a body is doubled, the coefficient of friction remains unaffected. The coefficient of friction is a constant property determined by the surfaces in contact and the materials involved. It does not change with alterations in the weight of the body or the applied force. Thus, even when the body’s weight is doubled, the coefficient of friction retains its original value.
VSAQ-3 : Why does the car with a flattened tyre stop sooner than the one with inflated tyres.
A car with a flattened tire stops sooner than one with inflated tires due to an increase in the area of contact between the tire and the road. This larger contact area results in a greater rolling frictional force, which is directly proportional to the contact area. The heightened rolling frictional force acts as a stronger opposing force to the car’s motion, causing it to decelerate more rapidly and consequently reducing the stopping distance. In contrast, a car with properly inflated tires has a smaller contact area and, therefore, experiences less rolling friction, leading to a longer stopping distance.
VSAQ-4 : What is inertia? What gives the measure of inertia?
Inertia is the property of an object that resists changes in its state of motion. It is a fundamental concept in physics. The measure of inertia is quantified by an object’s mass. The greater the mass of an object, the greater its inertia. In essence, mass is the measure of an object’s resistance to changes in its velocity, making it a crucial factor in determining how much force is required to accelerate or decelerate an object.
VSAQ-5 : If a bomb at rest explodes into two pieces, the pieces must travel in opposite directions. Explain.
When a bomb at rest explodes into two pieces, the resulting pieces must travel in opposite directions due to the principle of conservation of momentum. This principle states that the total momentum of a closed system remains constant unless acted upon by an external force. Since the bomb initially has zero momentum (as it’s at rest), the total momentum after the explosion must also be zero to obey this principle.
To achieve a total momentum of zero, the two pieces must have equal but opposite momenta. Therefore, they travel in opposite directions to ensure that their combined momentum cancels out, complying with the conservation of momentum.
VSAQ-6 : Why are spokes provided in a bicycle wheel?
Spokes in a bicycle wheel serve two key purposes. They distribute forces evenly to support the wheel’s strength and shape, and they reduce overall weight, making the wheel both robust and lightweight for efficient cycling.
VSAQ-7 : According to Newton’s third law, every force is accompanied by an equal and opposite force. How can movement ever take place?
Newton’s third law states that for every action, there is an equal and opposite reaction. This law does not prevent movement; it explains how movement occurs. When an object experiences a force, it exerts an equal and opposite force on another object. In the context of movement, it’s this reaction force that propels an object forward or initiates movement. Therefore, movement can take place precisely because of Newton’s third law, as the accompanying reaction force is responsible for initiating and sustaining motion.
VSAQ-8 : When a bullet fired from a gun, the gun gives a kick in the backward direction. Explain.
When a bullet is fired from a gun, the gun recoils or gives a “kick” in the backward direction due to the conservation of momentum. According to Newton’s third law of motion, every action has an equal and opposite reaction. When the bullet is accelerated forward by the force of the exploding gunpowder, it exerts an equal but opposite force backward on the gun itself. This backward force on the gun results in the gun’s recoil or kick. It’s the conservation of momentum that ensures the gun and the bullet move in opposite directions, following Newton’s third law.