Question

multiple select question select all that apply if a car has a mass of 1,500 kg and a velocity of 75 km/h west, to calculate the cars momentum in units of kg·m/s, you would need to □ replace velocity with speed. □ multiply mass by velocity. □ convert the mass to grams. □ convert km/h to m/s.

Explanation:

Step1: Ensure mass is in kg

The mass is already given in kg (1500 kg), so no need to convert it to grams. Converting to grams would be wrong as the unit for momentum calculation should be kg - m/s and mass should be in kg.

Step2: Convert velocity to m/s

We know that 1 km = 1000 m and 1 h=3600 s. To convert km/h to m/s, we use the conversion factor. If \(v = 75\ km/h\), then \(v=\frac{75\times1000}{3600}\ m/s\). So we need to convert km/h to m/s.

Step3: Use momentum formula

The formula for momentum \(p = mv\), where \(m\) is mass and \(v\) is velocity. We multiply the mass by the velocity (after converting velocity to m/s) to get the momentum in kg - m/s.

Step4: Differentiate velocity and speed

Velocity is a vector quantity and speed is a scalar quantity. For momentum calculation, we use velocity as it has both magnitude and direction. We cannot replace velocity with speed as momentum is a vector - related quantity.

Answer:

A. convert km/h to m/s.
C. multiply mass by velocity.