Acalculation used to estimate the answer to a problem before doing an actual calculation

At what time will the interfering waves have an amplitudeof zero?

Chameleons catch insects with their tongues, which they can rapidly extend to great lengths. in a typical strike, the chameleon's tongue accelerates at a remarkable 220 m/s2 for 20 ms, then travels at constant speed for another 30 ms.

Of is j/kg·k. if a 2.6 kg of isk to k,is ?