SI units, prefixes and checking units

Answer Key - Grade 11 Science Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   A car travels at 72 km/h. What is this speed in m/s, Ari?

   20 m/s
2. 2.

   A train travels at 90 km/h. What is this speed in m/s, Bo?

   25 m/s
3. 3.

   Work = force × distance. What is a joule in SI base units, Kira?

   • kg·m/s²
   • kg·m/s
   • kg·m²/s
   • kg·m²/s²
4. 4.

   Power = energy ÷ time. What is a watt in SI base units, Luz?

   • kg·m²/s³
   • kg·m/s³
   • kg·m²/s²
   • kg·m²·s
5. 5.

   “A car trip. Arrow grid in quantity boxes (example data). Each box holds one quantity:” Using the quantity boxes, which equation has the same units on both sides, Milo?

   • d = v × t
   • v = d × t
   • t = v × d
   • d = v ÷ t
6. 6.

   A classmate works out a ball's speed and gets 12 m/s². What does the unit tell Noah?

   • Something went wrong: speed is in m/s
   • The ball is speeding up
   • Nothing; the number is what counts
   • The speed was squared correctly
7. 7.

   Which quantity is measured in m/s², Pia?

   • Acceleration
   • Velocity
   • Distance
   • Force
8. 8.

   How is 3.2 × 10⁻⁶ m written with a prefix, Ren?

   • 3.2 mm
   • 3.2 Mm
   • 3.2 nm
   • 3.2 μm
9. 9.

   Light in a vacuum travels exactly 299,792,458 m/s (NIST). What is this to three significant figures, Tala?

   • 3.00 × 10⁷ m/s
   • 3.00 × 10⁸ m/s
   • 3.00 × 10⁹ m/s
   • 2.99 × 10⁸ m/s
10. 10.

    How many hertz is 4.7 GHz, Zee?

    • 4.7 × 10⁹ Hz
    • 4.7 × 10⁶ Hz
    • 4.7 × 10⁻⁹ Hz
    • 4.7 × 10³ Hz