Answer:

Explanation:
In this case we have to use the Principle of conservation of Momentum:
<em>This principle says that in a system the total momentum is constant if no external forces act in the system. The formula is:</em>

<em>Where:</em>
Mass of the first object.
Mass of the second object.
Initial velocity of the first object.
Initial velocity of the second object.
Final velocity of the first object.
Final velocity of the second object.
In <u>this problem</u> we have:


Observation:
Is because the system has the same initial velocity.
First we have to find
,

We can rewrite it as:

Replacing with the data:

We found the final velocity of the cart, but the problem asks for the resulting change in the cart speed, this means:

Then, the resulting change in the cart speed is:

First of all, you didn't tell us WHO measured the "10 years".
If it was the people on Earth, then 10 years passed according to them.
If it was 10 years on the space traveler's clock, then the clock in the
OTHER place, like on Earth, is subject to the relativistic 'time dilation'.
If the clocks are moving relative to each other, then the time interval measured
on either clock is equal to the interval measured on the other clock, divided by
√(1 - v²/c²) .
You said that v/c = 0.85 .
v²/c² = (0.85)² = 0.7225
1 - v²/c² = 1 - 0.7225 = 0.2775
√(1 - v²/c²) = √0.2775 = 0.5268
If one clock counts up 10 years, then the other one counts up
(10years) / 0.5268 = <em>18.983 years </em>
I believe that's the way to do this, and I'll gladly take your points,
but let me recommend that you get a second opinion before you
actually take off on your 10-year interstellar mission.
Metal cooking pots and pans often have wooden handles. Wood has a higher specific heat than metal, so it takes more energy to heat a wooden handle than a metal handle. As a result, a wooden handle would heat up more slowly and be less likely to burn your hand when you touch it.