Need with part b. is part a 140 times?

1680, and No

Step-by-step explanation:

Part A: A mockingbird beats its wings 420 times per 30 seconds (half a minute). This means that a mockingbird will beat its wings 840 times per minute. Multiply this by two and you get 1680 times in two minutes.

Part B: Divide the amount of beats in a minute by 60 (because there are 60 seconds in a minute) and you get the amount of times a mockingbird beats it wings per second.

420/30 = 14 times per second

Ariel said it was 0.07 times per second which is incorrect.

where is the figure

a. 12.5 kg

step-by-step explanation:

f = ma

so

m = f/a = (2500 n)/(200 m/s²) = 12.5 kg

1 n = 1 kg·m/s²