I\'m really stuck on these two questions in my physics post-lab, and any help wo
ID: 1329195 • Letter: I
Question
I'm really stuck on these two questions in my physics post-lab, and any help would be greatly appreciated!
I hope the picture is clear. In this lab we had a cart on a track attached to a weight by a string. We held the cart in place, until we were ready to record on LoggerPro. When we let go, the weight fell to the ground and the cart was pulled towards the end of the track. The mass of the weight is m and the mass of the cart is M. The questions I'm having trouble with:
1) Since the two objects move together, what is the relationship between the magnitudes of the accelerations of M and m?
2) Since the string is very light with negligible mass, what is the relationship between the tension force exerterted on M and the tension force exerted on m?
Explanation / Answer
a) as the two objects move together, the magnitude of acceleration of two objects is the same.
only difference will be in direction , for mass m it will be in negative y axis and for M it will be in positive x axis
mg - T = ma or T = mg - ma = m(g-a)
T = Ma
from above 2 equations :
Ma = m(g-a)
a=(mg)/(m+M) this is the magnitude of acceleration
b) Since the string is very light with negligible mass, we have no other forces on the two blocks other than that labelled in figure by you.
so tension is same in the two masses, again only difference is that there will be different directions for them. for M it will be along negative x axis. for m it will be downwards