|
Question 1187491: An object accelerates from rest at 3 m/s2 to the right with a net force of 280 N. Calculate the mass of the object and the distance it travels in 5 seconds.
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! You know the formulas  and  for distance traveled accelerating from rest.
You do not need to memorize formulas, you just need to understand them and think with your own head.
<-->  is intuitive.
If you need a lot more force to get the same acceleration for a car than for a baby carriage, it must be that the car is a lot heavier.
If you need 100 times the force, it must be 100 times heavier.
If the acceleration you achieve with the same force is a lot less for the car it's because its heavier.
Acceleration is the change in velocity per second (we can say velocity is speed, if we all go in the same direction).
We divide distance by time once to get speed, then divide again to get acceleration.
If it is   , starting from rest, the speed will be
3 m/s after 1 second
3 m/s + 3 m/s = 6 m/s after another second (2 seconds from the start)
9 m/s after 3 seconds
12 m/s after 4 seconds
15 m/s after 5 seconds
 For a constant 15 m/s speed, the graph would look like this  ,
and the distance traveled in 5 seconds would be the constant 15 m/s speed times the 5 second travel time.
That is the area of the rectangle between 0 and 5 seconds under the speed graph:
For a variable speed, the distance traveled is also the area under the speed curve.
For the problem that area is a triangle, half the rectangle, 37.5 m.
No formulas needed, but we can deduce them if we need them.
Accelerating from rest the "velocity"  is  ;
the area of the rectangle would be time times that velocity  ,
and the distance traveled is half of that .
|
|
|
| |
