Momentum - Conceptual Review

1. Momentum is a vector quantity.

• True

• False

Answer explanation

Momentum is a vector quantity. Like all vector quantities, the momentum of an object is not fully described until the direction of the momentum is identified. Momentum, like other vector quantities, is subject to the rules of vector operations.

Tags

NGSS.HS-PS2-2

1. The standard unit on momentum is the Joule.

• True

• False

Answer explanation

The Joule is the unit of work and energy. The kg m/s is the standard unit of momentum.

Tags

NGSS.HS-PS2-2

1. An object with mass will have momentum.

• True

• False

Answer explanation

An object has momentum if it is moving. Having mass gives an object inertia. When that inertia is in motion, the object has momentum.

Tags

NGSS.HS-PS2-2

2. An object which is moving at a constant speed has momentum.

• True

• False

Answer explanation

This is true. However, one should be quick to note that the object does not have to have a constant speed in order to have momentum.

Tags

NGSS.HS-PS2-2

1. An object can be traveling eastward and slowing down; its momentum is westward.

• True

• False

Answer explanation

The direction of an object's momentum vector is in the direction that the object is moving. If an object is traveling eastward, then it has an eastward momentum. If the object is slowing down, its momentum is still eastward. Only its acceleration would be westward.

Tags

NGSS.HS-PS2-2

1. Momentum is a conserved quantity; the momentum of an object is never changed.

• True

• False

Answer explanation

To say that momentum is a conserved quantity is to say that if a system of objects can be considered to be isolated from the impact of net external forces, then the total momentum of that system is conserved. In the absence of external forces, the total momentum of a system is not altered by a collision. However, the momentum of an individual object is altered as momentum is transferred between colliding objects.

Tags

NGSS.HS-PS2-2

1. The momentum of an object varies directly with the speed of the object.

• True

• False

Answer explanation

Momentum is calculated as the product of mass and velocity. As the speed of an object increases, so does its velocity. As a result, an increasing speed leads to an increasing momentum - a direct relationship.

Tags

NGSS.HS-PS2-2

1. Two objects of different mass are moving at the same speed; the more massive object will have the greatest momentum.

• True

• False

Answer explanation

For the same speed (and thus velocity), a more massive object has a greater product of mass and velocity; it therefore has more momentum.

Tags

NGSS.HS-PS2-2

1. A less massive object can never have more momentum than a more massive object.

• True

• False

Answer explanation

A less massive object would have a greater momentum owing to a velocity which is greater than that of the more massive object. Momentum depends upon two quantities * mass and velocity. Both are equally important.

Tags

NGSS.HS-PS2-2

1. Two identical objects are moving in opposite directions at the same speed. The forward moving object will have the greatest momentum.

• True

• False

Answer explanation

When comparing the size of two momentum vectors, the direction is insignificant. The direction of any vector would never enter into a size comparison.

Tags

NGSS.HS-PS2-2