Originally Posted By: paul
q: what is the amount of force that you would need to apply to a 100kg mass in order to accelerate it at a acceleration rate of .8 m/s/s for a distance of 1000 meters over a time period of 50 seconds.

answer: 4000N
80N x 50 seconds = 4000N




q: what is the amount of force that you would need to apply to a 100kg mass in order to accelerate it at a acceleration rate of .8 m/s/s?

answer 80N

q:over a time period of 50 seconds?

answer:4000N

did you read the question.
it ask what is the amount of force.
not what is the amount of momentum.
or what is the impulse force.



Originally Posted By: kallog
Again, no. You ignored the seconds. It should be 4000Ns which is an impulse, not a force. In this case impulse may be the more useful quantity because it captures the time that it took.

Correct answer:
F=ma
F=100kg * 0.8m/s^2
F=80N


what you are doing is accelerating the 100 kg mass to
.8 m/s/s for 1 second , it would only reach a velocity of
0.8 m/s in that 1 second.

and if 80N is all the force you can apply to the 100 kg mass
then after that 1 second you would no longer be accelerating the mass because you already used the force that you had.

so after you had applied the 80N force to the 100kg mass for a time of 1 second it would have 80Ns momentum
I didnt even have to calculate the momentum because the force caused its momentum.

and I know that the force applied was 80N

lets check it.

p=mv
p = 100kg x 0.8 m/s = 80Ns
yep...


it would keep going in zero g at a velocity of -0.8 m/s , but thats not what were doing here.

remember were accelerating the mass to -40 m/s not -0.8 m/s
ie..it needs to have a velocity of 40 m/s by the time it reaches the turn at a distance of 999.6 meters from where it was after you ran out of force.

OBVIOUSLY

your correct answer: is wrong.






3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.