How Do Acceleration-Time Graphs Explain Motion?

AI Thread Summary
The discussion focuses on analyzing the motion of a 2.0 kg body using acceleration-time graphs. Participants calculate the average acceleration as -0.5 m/s² and subsequently determine the average force acting on the body to be -1 N. There is clarification that the negative sign indicates the direction of the force, confirming that -1 N is correct. The calculations and graphs presented are validated by other participants. The conversation emphasizes the importance of understanding both the calculations and the implications of negative values in physics.
Spruance
Messages
33
Reaction score
0
A 2,0 kg body moves along a straight line.

bilde.gif


x={0,2,4,6,8,10,12,14,16,18,20} s
f(x)={10,10,20,30,50,50,50,20,10,5,0} m/s


a)
Make a acceleration-time graph

c)
Calculate the average force working on this body
 
Physics news on Phys.org
I tried to make a acceleration graph. However, something is wrong with it.

ww.png



c) First I tried to find the average acceleration,

a = ((v - v0)/(t-t1)) = (0 m/s - 10 m/s)/(20-0)) = -0,5 m/s^2

then

E = ma

= 2 kg * -0,5 m/s^2

= - 1 N


Can anyone correct me?
 
From the data given, both your graphs and calculations are correct. Why do you believe it be wrong?

~H
 
Ok. It is - 1 N, and not 1 N?
 
Spruance said:
Ok. It is - 1 N, and not 1 N?

Yes, it is -1N from the given data.

~H
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top