The measure of an object's mass and velocity is called a. gravity b. acceleration c. inertia d. momentum

The correct answer to the question is D. Momentum i.e the measure of mass and velocity is called momentum.

EXPLANATION:

The momentum of a body is defined as the amount of motion contained in the body.

Quantitatively momentum of  a body is the product of mass with velocity of the body.

Mathematically it can be written as momentum P = m × v

Here, m is the mass of the body and v is the velocity of the body.

The inertia of a body is defined as the property by virtue of which a body at rest will be at rest or a body moving with uniform velocity keeps on moving with the same velocity.

Quantitatively inertia is simply the measure of mass of the body.

The acceleration of a body is the rate of change of velocity. So, it can not be a measure of mass and velocity of a body.

Similarly gravity can not be considered as the measure of mass and velocity. It is so because it is the force with which any body on the surface of earth is attracted towards the centre of earth.

Hence, the correct answer will be momentum.

D. momentum

Explanation:

The momentum is defined as the linear momentum or amount of movement. In physics it is the fundamental quantity that characterizes the movement of any object. It is the product of the mass of a moving body and its linear velocity. The moment is a vector quantity, which means that it has magnitude, direction and meaning. The total linear momentum of a system consisting of a series of objects is the vector sum of the moments of each individual object. In an isolated system, the total moment remains constant over time; It is what is called conservation of linear momentum.

For example, when a tennis player hits a ball, the linear moment of the racket just before hitting the ball plus the moment of the ball at that moment is equal to the moment of the racket immediately after hitting the ball plus the moment of The ball hit. In another example, let's imagine a swimmer who jumps from a still boat that floats on water. Before jumping, the boat and the swimmer do not move, so the total linear moment is zero. When jumping, the swimmer acquires linear momentum forward, and at the same time the boat moves backwards with a moment equal in magnitude and direction but opposite direction; the total moment of the system formed by the swimmer and the boat remains null.

Current physics considers the conservation of momentum as a universal law, which is fulfilled even in extreme situations where the classical theories of physics are not valid. In particular, the conservation of linear momentum is fulfilled in quantum theory, which describes atomic and nuclear phenomena, and in relativity, which is used when systems move at speeds close to that of light.