The force that a moving object exerts on another object upon colliding with it is rather the change in momentum divided by the amount of time elapsed during the collision.
F = Δp/Δt
F = force, Δp = change in momentum, Δt = elapsed time
Usually we say momentum is proportional to mass instead of saying momentum is proportional to weight. But sure, for two objects on the same planet, greater weight implies greater mass. Momentum is the product of mass and velocity:
p = mv
p = momentum, m = mass, v = velocity
So we have two identical cars on the same planet with one car traveling 30mph faster than the other. Let's say they both collide with a tree, both coming to a rest, and the collisions take the same amount of time to happen. The faster car loses a greater amount of momentum over the same amount of time, therefore delivering a greater force.
Choice B
The last choice on the list is the correct one, for both #2 and #3.
Answer:
A. The number of valence electrons increases by 1.
Explanation:
As you move across any period on the periodic table, the number of valence electrons increases by a value of 1.
- The periodic table of elements contains an arrangement of element by their atomic numbers.
- From left to right, number of valence electrons increases.
- Down a group, the valence electrons are the same.
- Across a period, the number of valence electrons increases.
It would be A. 37.5 because if you multiply 50 and 15 it would be 750 then divide 20 it gives you 37.5.
Sound waves can travel through ANY material ... solid, liquid, or gas.
The thing is: Sound NEEDS material to travel through, and if there's
nothing there, then sound can't go anywhere. The correct choice
on the list is 'D' ... Sound can't travel through vacuum, because
there's nothing there. When we talk to each other, the AIR between
us carries the sound waves.
Have you ever seen any video of two astronauts standing on the
moon, or two astronauts "space-walking" on the outside of the
Space Shuttle ?
Naturally, they have their helmets on, and they're talking to
each other. How are they talking ? No matter how close together
they are, they're talking to each other by radio ! because there's
nothing between them to carry sound. Even if they're only a few
inches apart, they can SHOUT but the other one can't hear it.
I have read ... I don't think there's any video of this ... that sometimes
when two astronauts are very close together, they can talk if they
touch their helmets together. Then the sound vibrations can go from
one helmet over to the other one, through the solid shell of the helmets.
