Fairly easy acceleration problem stumping me

[alpinecg]

1.Calculate the amount of force required to bring to rest an object of 900 Kg mass that moves with a speed of 20 m/s. The moving object is brought to rest in a time equal
to 0.1 s. Provide your answer in both N and KN units.



i think to solve this i just need to find force F=M x A



3. I divided 20m/s by the time interval of 0.1s to get acceleration then timed it by the mass of 900kg. the answer i got is 1,800,000N or 1800KN

 

[ehild]

Are not there too many 0-s?

ehild

 

[alpinecg]

ah yes i times the 0.1 by 200m/s not 20m/s so the answer would be 180,000N or 180KN

 

[ehild]

Correct

ehild