Physics Chapter 2 Momentum Review - Simplified & Final

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What is momentum?

• Mass times velocity of an object

• Collisions conserving momentum and kinetic energy

Answer explanation

Momentum is a fundamental concept in physics. It's calculated by multiplying the mass of an object by its velocity. This means, the greater the mass and velocity of an object, the greater its momentum. So, the correct answer to the question 'What is momentum?' is 'Mass times velocity of an object'.

What is the equation for momentum?

• J = F * t

• p = m * v

Answer explanation

The equation for momentum is 'p = m * v', where 'p' denotes momentum, 'm' denotes the mass of the object, and 'v' is its velocity. This equation is fundamental to Newtonian physics and expresses that momentum equals mass times velocity. The other options are not correct as they represent different physical concepts.

Which is an example of an elastic collision?

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Answer explanation

An elastic collision is the one where both momentum and kinetic energy are conserved. The best example of this is a game of billiards where the balls bounce off each other and the walls of the table, without losing energy.

What is impulse?

• Force applied to an object for a time period

• Collisions conserving momentum and kinetic energy

Answer explanation

Impulse is defined as the change in momentum of an object when the object is applied an external force for an interval of time. Therefore, the correct answer to the question is that impulse is the force applied to an object for a time period.

On what does momentum not depend?

• Force

• Acceleration

Answer explanation

Momentum, in physics, depends on the mass and velocity of an object. It is the product of the two. Force, on the other hand, is not a factor in calculating momentum. Force is related to acceleration, as indicated by Newton's second law of motion, but it does not directly influence an object's momentum. Therefore, momentum does not depend on force.

What is the law of conservation of momentum?

• Mass times velocity of an object

• Total momentum before and after a collision are equal

Answer explanation

The law of conservation of momentum states that the total momentum of an isolated system remains constant if no external forces act on it. This means that the total momentum before and after a collision must be equal, as indicated in the correct answer option. Other options are descriptions of different physics concepts, not the conservation of momentum.

What is an inelastic collision?

• Collisions where objects rebound with the same kinetic energy and momentum

• Collisions where some kinetic energy is converted into other energy forms

Answer explanation

An inelastic collision is one where some of the kinetic energy is converted into other forms of energy during the collision. This happens due to internal friction, sound, heat, etc. Hence, it's correct to say that an inelastic collision is a collision where some kinetic energy is converted into other energy forms.

What is the equation for impulse?

• p = m * v

• J = F * t

Answer explanation

The equation for impulse is represented as J = F * t. Impulse (J) is the integral of a force (F), F, over the time interval (t) for which it acts. Therefore, impulse is the change in momentum of an object when the object is subject to force over an interval of time. So, the correct answer to the question is 'J = F * t'.

What is the purpose of safety features in vehicles?

• To decrease velocity of center of mass

• To increase rest time and reduce force

Answer explanation

The purpose of safety features in vehicles is to protect the passengers from harm during accidents. This is achieved by increasing the amount of time it takes the body to stop moving, hence reducing force. This aligns with the answer, 'To increase rest time and reduce force'. This doesn't mean to rest more, but rather to extend the time of impact, reducing the force experienced.