If only internal forces are doing work (no work done by external forces), then there is no change in the total amount of mechanical energy. The total mechanical energy is said to be conserved. ... In these situations, the sum of the kinetic and potential energy is everywhere the same.
Answer:
An Energy held by an object because of its position relative by other objects
Explanation:
Lets do
We know
The rate of change of velocity is acceleration .


Integrate both sides

As acceleration is constant .Take it outside of integral .On velocity we can take limit u to v and time from 0 to t

Hence



The momentum of the two carts will be the same
Explanation:
First of all, we notice that the system consisting of the two carts + the spring is an isolated system: this means that there are no external forces acting on it.
As a result, the total momentum of the system must be conserved.
Since the spring is at rest, the total momentum of the system after the two carts are released is:

where
is the momentum of the 1st cart
is the momentum of the 2nd cart
The total momentum of the system at the beginning, when the spring is compressed, is zero:

Since the total momentum must be conserved, we have:

Which means that the two carts will have equal and opposite momenta.
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Answer:
The speed of the raft is 1.05 m/s
Explanation:
The equation for the position of the stone is as follows:
y = y0 + v0 · t + 1/2 · g · t²
Where:
y = height of the stone at time t
y0 = initial height
v0 = initial speed
t = time
g = acceleration due to gravity
The equation for the position of the raft is as follows:
x = x0 + v · t
Where:
x = position of the raft at time t
x0 = initial position
v = velocity
t = time
To find the speed of the raft, we have to know how much time the raft traveled until the stone reached the river. For that, we can calculate the time of free fall of the stone:
y = y0 + v0 · t + 1/2 · g · t² (v0=0 because the stone is dropped from rest)
If we place the origin of the frame of reference at the river below the bridge:
0 m = 95.6 m - 9.8 m/s² · t²
-95.6 m / -9,8 m/s² = t²
t = 3.12 s
We know that the raft traveled (4.84 m - 1.56 m) 3.28 m in that time, then the velocity of the raft will be:
x/t = v
3.28 m / 3.12 s = v
v = 1.05 m/s