Friction exists only when two objects rub against each other. A.True B.False
2 answers:
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Answer:
The magnitude of the force F is given by
F = ( +
+
) *(
*g/(
))
Explanation:
Given there are three blocks of masses ,
and
(ref image in attachment)
When all three masses move together at an acceleration a, the force F is given by
F = ( +
+
) *a ................(equation 1)
Also it is given that does not move with respect to
, which gives tension T is exerted on pulley by
only, Hence tension T is
T = *a ..........(equation 2)
There is also also tension exerted by . There are two components here: horizontal due to acceleration a and vertical component due to gravity g. Thus tension is given by
T =
................(equation 3)
From equation 2 and 3, we get
*a =
Squaring both sides we get
*
=
* (
+
)
*
= (
*
)+ (
*
)
( -
) *
=
*
=
*
/(
-
)
Taking square root on both sides, we get acceleration a
a = *g/(
)
Hence substituting the value of a in equation 1, we get
F = ( +
+
) *(
*g/(
))
Let say the two train cars are of masses and
now if the speed of two cars are and
then we can say that the momentum of two cars before they collide is given by
here two cars are moving in opposite direction so we can say that the net momentum is subtraction of two cars momentum.
Now since in these two car motion there is no external force on them while they collide
So the momentum of two cars are always conserved.
hence we can say that the final momentum of two cars will be same after collision as it is before collision