Can someone help me ?? :( A tennis ball moving with velocity 20 m s-1 towards a racquet. The ball is struck by the racquet so that it moves back in the opposite direction at 30 m s-1. If the racquet remains in contact with the ball for 0.02 s, find the average acceleration impacted by the racquet onto the tennis ball.
The answer : -2500 ms-2​

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =

the force represented by vector a is normal force. if the hockey puck is moving to the right, when it is hit with a significant force by the hockey stick the puck will move off in a different direction. correct on edge.