Find the dimensions of (a) density, (b) impulse (force times time), (c) surface tension (force per…

Step 1. (a) Density $= m/V$: $[\text{M}\,\text{L}^{-3}]$.

Step 2. (b) Impulse $= F t$: $[\text{M}\,\text{L}\,\text{T}^{-2}][\text{T}] = [\text{M}\,\text{L}\,\text{T}^{-1}]$, like momentum.

Step 3. (c) Surface tension $= F/l$: $[\text{M}\,\text{T}^{-2}]$, no length left.

Step 4. (d) Angular velocity $= \theta / t$, and an angle is a pure number: $[\text{T}^{-1}]$.