Answer:
1. a 
b 
c 
2. 
Explanation:
a). The work done by the tension is:




b). The work done potential of gravity




c). The work done by the normal force



2. The increase in thermal energy is:





Answer:

Explanation:
First of all, let's remind that:
- The kinetic energy of an object is given by
, where m is the mass and v is the speed
- The momentum of an object is given by 
- The inertia of an object is proportional to its mass, so we can write
, where k just indicates a constant of proportionality
In this problem, we have:
-
(the two objects have same kinetic energy)
-
(A has three times the momentum of B)
Re-writing both equation we have:

If we divide first equation by second one we get

And if we substitute it into the first equation we get

So, B has 9 times more mass than A, and so B has 9 times more inertia than A, and their ratio is:

1). trajectory
2). person sitting in a chair
3). 490 meters
4). 65 m/s
5). False. The projectile's displacement, velocity, and acceleration have vertical and horizontal components, but the projectile doesn't.
6). False
7). The vertical component of a projectile doesn't change due to gravity, but the vertical components of its displacement, velocity, and acceleration do.
The vertical components do NOT equal the horizontal components.
8). Decreasing if you include the effects of air resistance. Constant if you don't. Gravity has no effect on horizontal velocity.
9). We can't see the simulation. But if the projectile doesn't have jets on it, then as it travels upward, its vertical velocity must decrease, because gravity is trying to not let it get away.
10). We can't see the simulation. But if the projectile is traveling downward, we would call that "falling", and its vertical velocity must increase, because gravity is pulling it downward.
ITS C
This element tends to lose 2 electrons to become a 2+ ion, is the correct statement regarding the element calcium. Calcium has 2 electrons in its outer shell and it is easier to lose them than it is to gain enough to become stable. When stable it has 2 more protons than electrons forming a 2+ ion.
Risks are only in a persons