The mass number of an isotope is the sum of the numbers of protons and the numbers of the neutron. Given that the mass number is 65 and the number of neutrons is 35, the number of protons is 30. The atom is then Zinc (Zn). The charge is equal to +2, as it lacks 2 more electrons.
It's velocity is not constant as direction is changing.
We know, velocity is speed with direction, so if direction is changing, velocity can't be constant, doesn't matter that speed is constant.
Hope this helps!
It doesn't matter. If the slides are truly frictionless, then
your kinetic energy at the bottom will be equal to the
potential energy you had at the top, no matter what kind
of route you took getting down.
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The only way I can think of that it would make a difference
would be if the shallow slide were REALLY REALLY long,
and you didn't have anything to eat all the way down.
Then you might lose some weight while you're on the slide,
and your mass might be less at the bottom than it was at the
top. Then, in order to have the same kinetic energy at the
bottom, you'd need to be going a little bit faster.
But if it takes less than, say, two or three days, to go down the
long, shallow slide, then this effect would probably be too small
to make any difference.
ANSWER
Both trucks will move together with speed v = 6.67 m/s
so correct answer will be
The speed of the combined vehicles is less than the initial speed of the truck.
EXPLANATION
As we know that there is no external force on the system of two trucks
So here momentum of the two trucks before collision and after collision will remain same
So here we will have

so here we will have




now we will have


so correct answer will be
The speed of the combined vehicles is less than the initial speed of the truck.