levo

Dynamics

Linear momentum

  • 3 things to know
  • Component 1

Overview

Recall questions on the definition of momentum and its unit, momentum as a vector and what that means for a sign convention, the principle of conservation of linear momentum and the condition for it, and worked one-dimensional collision and explosion calculations.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Key term

State the equation for linear momentum, defining every symbol and its unit.

Key term

Define linear momentum.

Key term

Is momentum a scalar or a vector? Justify the answer.

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Define linear momentum.

    Model answer

    Linear momentum is the product of a body's mass and its velocity.

  2. 2

    State the equation for linear momentum, defining every symbol and its unit.

    Model answer

    The equation is p = mv, where p is momentum in kg m s⁻¹, m is mass in kg and v is velocity in m s⁻¹.

  3. 3

    Is momentum a scalar or a vector? Justify the answer.

    Model answer

    Momentum is a vector, because it is a scalar mass multiplied by a velocity, and the velocity carries a direction.

  4. 4

    Show that kg m s⁻¹ and N s are equivalent units.

    Model answer

    One newton is 1 kg m s⁻², so N s is kg m s⁻² × s = kg m s⁻¹.

  5. 5

    A car of mass 1500 kg travels north at 20 m s⁻¹. Calculate its momentum.

    Model answer

    The momentum is 1500 × 20 = 3.0 × 10⁴ kg m s⁻¹ directed north. Dividing 3.0 × 10⁴ kg m s⁻¹ by 1500 kg returns 20 m s⁻¹.

  6. 6

    A bullet of mass 9.0 g leaves a rifle at 400 m s⁻¹. Calculate its momentum.

    Model answer

    The momentum is 0.0090 × 400 = 3.6 kg m s⁻¹ in the direction of travel. Dividing 3.6 kg m s⁻¹ by 0.0090 kg returns 400 m s⁻¹.

Other ways to work this

The same content, four other ways.

What is inside Levo

Six ways to work the same material.

1Closed book
2Open book
3Closed book

The 3-step method, run for you

Answer cold, learn it, then prove it stuck. Levo tracks the jump between your first attempt and your last.

Basic Physics
Kinematics
Dynamics
Energy Concepts

Cram a whole paper in one sitting

Sort every topic into what you know and what you do not, then drill only the weak ones.

The wires .
attractrepeltwist

Blank Blitz makes facts automatic

Rapid timed gap-fills on the terms and numbers you need to recall without thinking.

AThe equation is pV = NkT.
BThe pressure, p, is in Pa.
CThe volume V is in m³.

Build It gets the exam shape right

Assemble a full-mark answer from its marking points, in the order an examiner wants them.

The joule is a unit of energy.
TrueFalse

Test It catches misconceptions

Spot the fault in a statement. The traps are the mistakes students actually make.

721941163128510

Brain Breaks between sessions

Short focus games to reset attention, so the next set lands better than the last.

Every question in Dynamics, on a schedule.

Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.

Or £46 a year, about £3.83 a month. Cancel anytime.