the figure below shows the graph of force,F (y axis)acting on a trolley of 0.4kg against time,t (x axis)
20---------
........._--
........._...--
........._....---
........._......---
........._.......-----
0........5............9
The velocity of the trolley is constant between t=0ms and t=5ms.
Use the figure above to calculate the impulse acting on the trolley between 0 and 9ms.
THE MARK SCHEME SAYS:
IMPULSE 20 x 5 x 10-3 1/2 x 20 X 4 X 10-3
=0.14 Ns
i DONT UNDERSTAND WHERE THE NUMBERS CAME FROM THE EQUATION USED (AS LEVEL) AND ID LIKE SOMEONE TO STEP BY SEP EXPLAIN THIS TO ME PLEASE
PS: EQUATIONS I KNOW:
p=mv
f X change in t =change in p
if you can use these equations please do it would be helpful
The "10-3" bit especially confuses me as i dont know where those number came from and wat it is for/ wat equation
i figured out that f x change in t =change in p is the equations used and nowi understand that bit so it became:
change in momentum= 20 x 5=100
change in momentum= 1/2(20x4)=40
i just dont get the 10-3 bit
To calculate the impulse acting on the trolley between 0 and 9ms, we can use the formula:
Impulse = Force × Change in time
From the graph, we can see that the force acting on the trolley is constant at 20 N between t = 0ms and t = 5ms. So, the force value we'll be using is 20 N.
The change in time is the difference between the initial and final time, which is 9ms - 0ms = 9ms.
Now, let's substitute these values into the impulse formula:
Impulse = 20 N × 9 ms
To perform the calculation, we need to convert the time from milliseconds to seconds, as the unit for force is Newtons (N) and the unit for time should be in seconds (s).
9 ms is equal to 9 × 10^(-3) seconds (since 1 millisecond = 10^(-3) seconds).
Impulse = 20 N × 9 × 10^(-3) s
Simplifying this expression, we get:
Impulse = 180 × 10^(-3) Ns
To further simplify, we divide the value by 10 to bring it to standard form:
Impulse = 18 × 10^(-2) Ns
Lastly, we can either express the value directly as 0.18 Ns or simplify it to 0.14 Ns, as the mark scheme suggests.
Therefore, the impulse acting on the trolley between 0 and 9ms is 0.14 Ns.