(a)[3]
An X-ray wave has a frequency of $4.6 \times 10^{20}\,\text{Hz}$. Calculate its wavelength in $\text{pm}$.
(b)[2]
A star is $8.5 \times 10^{16}\,\text{m}$ from Earth. Calculate the light travel time from the star to Earth in $\text{Gs}$.
(c)[1]
The list below includes both scalar and vector quantities. Underline every scalar quantity: acceleration, force, mass, power, temperature, weight.
(d)
A boat moves in a river current. Fig. 1.1 gives the velocity vectors for the boat and the river water. The boat’s velocity in still water is $14.0\,\text{m s}^{-1}$ to the east. The water’s velocity is $8.0\,\text{m s}^{-1}$ from $60^\circ$ north of east.