Answer:
A. the internal energy stays the same
Explanation:
From the first law of thermodynamics, "energy can neither be created nor destroyed but can be transformed from one form to another.
Based on this first law of thermodynamic, the new internal energy of the gas is the same as the internal energy of the original system.
Therefore, when the partition separating the two halves of the box is removed and the system reaches equilibrium again, the internal energy stays the same.
Answer:
The work done on the canister is 15.34 J.
Explanation:
Given;
mass of canister, m = 1.9 kg
magnitude of force acting on x-y plane, F = 3.9 N
initial velocity of canister in positive x direction,
= 3.9 m/s
final velocity of the canister in positive y direction, 
The change in the kinetic energy of the canister is equal to net work done on the canister by 3.9 N.
ΔK.E = 
ΔK.E 
The initial kinetic energy of the canister;

The final kinetic energy of the canister;

ΔK.E = 29.79 J - 14.45 J
ΔK.E =
= 15.34 J
Therefore, the work done on the canister is 15.34 J.
Answer:
Janet jumps off a high diving platform with a horizontal velocity of 2.89 m per s and lands in the water 1.5 s later. How high is the platform?
Platform is 11.025 meters high .
Explanation:
we have Vx = 2.89 m/s
time taken = 1.5 seconds
height of the platform = ?
so,
As Janet is jumping from a high diving platform from a certain unknown height their must be involvement of gravity in action.
we can use,
h = Vi*t+(1/2)*g*t^2
where ,
h = height
Vi = initial horizontal velocity that will be zero
t = time in seconds
g = gravity due to acceleration
now put the values
h = 0+(1/2)*(9.8)*(1.5)^2
h = 11.025-m
Recall that

where
and
are the lion's initial and final vertical velocities,
is its acceleration, and
is the vertical displacement.
At its maximum height, the lion has 0 vertical velocity, so we have

where <em>g</em> is the acceleration due to gravity, 9.80 m/s², and we take the starting position of the lion on the ground to be the origin so that
.
Let <em>v</em> denote the initial speed of the jump. Then
