SI units and prefixes Transitional Reasoning Download PDF

Questions

1. 1.

   During a safety evaluation of an automated transport cart, a braking system decelerates the cart from an initial velocity of 54 km/h to a complete stop over a time interval of 25 ms. The magnitude of average acceleration is defined by the relationship $a = \frac{|\Delta v|}{\Delta t}$. What is the magnitude of the cart's average acceleration expressed in the coherent SI unit of m/s$^2$?

   • A) 0.60 m/s$^2$
   • B) 60 m/s$^2$
   • C) 600 m/s$^2$
   • D) 2160 m/s$^2$
2. 2.

   An ultrasound transducer used in medical imaging generates an acoustic wave that propagates through muscle tissue at a speed of 1500 m/s with a wavelength of 0.75 mm. The frequency of a wave is related to its speed and wavelength by the formula $f = v/\lambda$. What is the frequency of this ultrasound wave expressed in megahertz (MHz)?

   • A) 0.020 MHz
   • B) 0.20 MHz
   • C) 20 MHz
   • D) 2.0 MHz
3. 3.

   During an orbital impact study, researchers analyze a high-speed micrometeoroid with a mass of 0.20 mg traveling at a velocity of 3.0 km/s relative to a spacecraft shield. The kinetic energy of an object is given by $E_{\text{k}} = \frac{1}{2}mv^2$. What is the kinetic energy of the micrometeoroid expressed in the coherent SI unit of energy (joules)?

   • A) $0.90\text{ J}$
   • B) $1.8\text{ J}$
   • C) $900\text{ J}$
   • D) $9.0 \times 10^{-4}\text{ J}$
4. 4.

   In a thin-film deposition facility, a protective coating is applied to a semiconductor wafer at a steady rate of 0.40 nm per second. The automated process runs continuously for a total duration of 2.5 hours. What is the final thickness of the deposited coating expressed in micrometers (µm)?

   • A) 0.060 µm
   • B) 3.6 µm
   • C) 36 µm
   • D) 3600 µm
5. 5.

   A wearable biosensor designed for continuous cardiac monitoring consumes an average power of 250 μW. To size an energy-harvesting cell for the device, an engineer evaluates its total energy demand over an operating span of 40 hours. In the coherent SI unit for energy (joules), what is the total energy consumed by the biosensor during this time?

   • A) 0.010 J
   • B) 0.60 J
   • C) 36 000 J
   • D) 36 J
6. 6.

   A materials scientist synthesizes a polymer sample in the shape of a cube to verify its mass density. The mass of the cube is measured as 54 mg, and the length of each edge is measured as 3.0 mm. Which of the following correctly expresses the density of the polymer in the coherent SI unit, $\text{kg}/\text{m}^3$?

   • A) $2.0 \times 10^6\text{ kg}/\text{m}^3$
   • B) $2.0 \times 10^3\text{ kg}/\text{m}^3$
   • C) $2.0\text{ kg}/\text{m}^3$
   • D) $2.0 \times 10^{-3}\text{ kg}/\text{m}^3$
7. 7.

   In an introductory physics laboratory, a student analyzes the electrical resistance of a circuit component using the relationship $R = \frac{V}{I}$. The electric potential difference is defined as work per unit charge, $V = \frac{W}{q}$, where electric charge satisfies $q = I \cdot t$. If work is expressed in fundamental SI base units as $\text{kg}\cdot\text{m}^2\cdot\text{s}^{-2}$, which of the following correctly expresses the derived SI unit for resistance, the ohm ($\Omega$), entirely in fundamental SI base units?

   • A) $\text{kg}\cdot\text{m}^2\cdot\text{s}^{-2}\cdot\text{A}^{-1}$
   • B) $\text{kg}\cdot\text{m}^2\cdot\text{s}^{-3}\cdot\text{A}^{-2}$
   • C) $\text{kg}\cdot\text{m}\cdot\text{s}^{-3}\cdot\text{A}^{-2}$
   • D) $\text{kg}\cdot\text{m}^2\cdot\text{s}^{-1}\cdot\text{A}^{-2}$
8. 8.

   A laser laboratory records the durations of three optical pulses during an instrument calibration: Pulse X: 2.5 ns Pulse Y: 0.04 μs Pulse Z: 3500 ps Which of the following correctly ranks these pulses in order from shortest to longest duration?

   • A) Pulse Y < Pulse Z < Pulse X
   • B) Pulse Z < Pulse X < Pulse Y
   • C) Pulse X < Pulse Z < Pulse Y
   • D) Pulse X < Pulse Y < Pulse Z