A wave machine vibrates the end of a rope at 4 Hz, making waves 2 m long. How fast do they travel?
No stopwatch is needed. The 4 Hz and the 2 m are enough, because v = fλ turns a frequency and a wavelength straight into a speed.
Write down what is known: f = 4 Hz, λ = 2 m, v = ?
Write down the equation: v = fλ. The unknown, v, already stands alone on one side.
Substitute and calculate: v = 4 × 2 = 8. The waves travel at 8 m/s.
The unit takes care of itself: Hz times m gives m each second, so the answer lands in m/s.
A wave machine vibrates the end of a rope at 4 Hz, making waves 2 m long. Calculate the wave's speed.
Write down the values:
f = 4 Hz, λ = 2 m, v = ?
Write down the equation:
v = fλ
Substitute in the values, and calculate:
v = 4 × 2 = 8
The waves travel at 8 m/s.
A speaker makes a sound wave in air with frequency 50 Hz and wavelength 6.8 m. Calculate the sound wave's speed.
Write down the values:
f = 50 Hz, λ = 6.8 m, v = ?
Write down the equation:
v = fλ
Substitute in the values, and calculate:
v = 50 × 6.8 = 340
The sound wave's speed is 340 m/s.
Ripples on a pond have frequency 2.5 Hz and wavelength 1.2 m. Enter the wave's speed, in m/s.
Waves on a heavy chain have frequency 6 Hz and wavelength 0.85 m. Enter the wave's speed, in m/s.
A wave travels along a stretched garden hose with frequency 12 Hz and wavelength 0.45 m. Enter the wave's speed, in m/s.
A long spring stretched down a school hallway carries waves of frequency 7.5 Hz and wavelength 1.4 m. Enter the wave's speed, in m/s.
A speaker plays a steady tone, making a sound wave in air with frequency 80 Hz and wavelength 4.2 m. Enter the sound wave's speed, in m/s.
In a ripple tank, the dipper makes ripples with frequency 9 Hz and wavelength 0.03 m. Enter the wave's speed, in m/s.