Recall the wave equation,

where c is the speed of the wave (m/s), f is the frequency of the wave (Hz) and λ is the wavelength of the wave (m).

so
Answer:
20 N in West direction.
Explanation:
opposite forces cancel each other. so 20 N in north and 20N in south cancel each other. In west and east direction...
70N in west-50N in east= 20N in west



When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. The gas is formed in the reaction is Carbon dioxide.
is formed.
The change which happened in this reaction is a chemical change.

Since, in chemical change we can't bring a substance to it's actual form how it was in earlier.
Examples: burning of paper is chemical, since we can't get the fine paper again after it is burnt.
Thus, the above reaction is also a chemical change, since we can't get back the lemon juice how it was earlier.

D. 980, this is the best answer because 35 x 7 is 980 :)