1) C. velocity
Acceleration is defined as the rate of change of velocity per unit time. In formulas:

where
is the change in velocity
is the time interval
Therefore, the correct answer is C. velocity.
2) A. 9.8m/s/s
Earth's gravity is a force, so it produces an acceleration on every object with mass located on the Earth's surface. This acceleration can be calculated, as it is given by the formula

where
is the gravitational constant
is the Earth's mass
is the Earth's radius
By substituting these numbers into the formula, one can find that the acceleration due to Earth's gravity is
.
Troposphere is the answer
Answer:
Force, 
Explanation:
Given that,
Mass of the bullet, m = 4.79 g = 0.00479 kg
Initial speed of the bullet, u = 642.3 m/s
Distance, d = 4.35 cm = 0.0435 m
To find,
The magnitude of force required to stop the bullet.
Solution,
The work energy theorem states that the work done is equal to the change in its kinetic energy. Its expression is given by :

Finally, it stops, v = 0



F = -22713.92 N

So, the magnitude of the force that stops the bullet is 
Answer:
8.6 m
Explanation:
The motion of a soccer ball is a motion of a projectile, with a uniform motion along the horizontal (x-) direction and an accelerated motion along the vertical (y-) direction, with constant acceleration
towards the ground (we take upward as positive direction, so acceleration is negative).
The initial velocity along the vertical direction is

Now we can consider the motion along the vertical direction only. the vertical velocity at time t is given by:

At the point of maximum height,
, so we can find the time t at which the ball reaches the maximum height:

And now we can use the equation of motion along the y-axis to find the vertical position of the ball at t=1.33 s, which corresponds to the maximum height of the ball:

Answer:
B. learning happens through experience and practice.