Question

what are the correct units for momentum? choose all that apply. *
n*m
j
kg
kg*m/s
j*s
m
n*s
which of the following statements is false? *
momentum is a vector quantity because it does not have direction.
increasing the mass of an object increases the momentum.
increasing the velocity of an object increases the momentum.
only objects in motion have momentum.
which of the following statements are true? check all that apply. *
momentum is a vector quantity because it depends on velocity (which is also a vector quantity).
momentum is directly proportional to both mass and velocity.
objects at rest have no momentum.
momentum only occurs when an object experiences unbalanced forces.
objects traveling at a constant velocity have momentum.

Explanation:

• For units of momentum:
• The formula for momentum is \(p = mv\), where \(m\) is mass (unit \(kg\)) and \(v\) is velocity (unit \(m/s\)). So the unit of momentum is \(kg\cdot m/s\).
• Also, from the impulse - momentum theorem \(J=\Delta p\), and impulse \(J = F\Delta t\) (where \(F\) is force with unit \(N\) and \(\Delta t\) is time with unit \(s\)), so \(N\cdot s\) is also a unit of momentum (\(1N = 1kg\cdot m/s^{2}\), then \(N\cdot s=kg\cdot m/s\)).
• For the false statement:
• A vector quantity has both magnitude and direction. Momentum \(p = mv\), and since velocity \(v\) is a vector, momentum is a vector. The statement “Momentum is a vector quantity because it does not have direction” is wrong.
• For the true statements:
• Since \(p = mv\) and \(v\) is a vector, momentum is a vector.
• From \(p = mv\), momentum is directly proportional to both \(m\) and \(v\).
• If \(v = 0\) (object at rest), then \(p=mv = 0\).
• For an object traveling at a constant velocity \(v

eq0\) and \(m>0\), \(p = mv
eq0\). Momentum does not depend on unbalanced forces (it depends on mass and velocity), so the statement “Momentum only occurs when an object experiences unbalanced forces” is wrong.

Answer:

• Correct units for momentum: \(kg\cdot m/s\), \(N\cdot s\)
• False statement: Momentum is a vector quantity because it does not have direction.
• True statements:
• Momentum is a vector quantity because it depends on velocity (which is also a vector quantity).
• Momentum is directly proportional to both mass and velocity.
• Objects at rest have no momentum.
• Objects traveling at a constant velocity have momentum.