Could someone check these practice test questions over for me? I'm not good at physics at all, so I would love an explanation.

1. A projectile is shot an angle into the air. Neglecting air resistance...
1a. It's horizontal acceleration is
a) 9.8 m/s^2
b) 0.0 m/s^2 ***
c) 10 m/s
1b. It's downward acceleration is
a) 9.8 m/s^2 ***
b) 0.0 m/s^2
c) 10 m/s
1c. It's vertical acceleration is
a) 9.8 m/s^2
b) 0.0 m/s^2
c) 10 m/s ***

2. Choose the right answer each matching case below:
2a. The rate of change of velocity is
a) velocity
b) speed
c) time
d) acceleration ***
e) distance
f) gravity
2b. The rate of change of anything is always with respect to
a) velocity
b) speed
c) time ***
d) acceleration
e) distance
f) gravity
2c. The rate of change of displacement is
a) velocity ***
b) speed
c) time
d) acceleration
e) distance
f) gravity

3. The units of speed are:
a) m/s
b) m/s^2 and direction
c) N
d) m/s and direction ***

4. The displacement of an airplane from its starting point is 200 km at 60 degrees NE. Its easterly component is:
a) 173.2 km
b) 200 km
c) 100 km

#1 Lose the apostrophes

1a, 1b look good
1c cannot be right, since m/s is not acceleration.

#2 all ok

#3 is (a) - speed has no direction.
(c) is for velocity

#4. Not sure what 60° NE means.
I know N 60° E and E 60° N.

In any case, draw the direction and take the horizontal component, using sine or cosine as appropriate.

To check the practice test questions, let's break them down one by one and explain how to arrive at the correct answer.

1. A projectile is shot at an angle into the air. Neglecting air resistance...
1a. The horizontal acceleration of a projectile is 0.0 m/s^2. This is because there is no force acting horizontally on the projectile once it is in the air. Therefore, the correct answer is b) 0.0 m/s^2.

1b. The downward acceleration of a projectile is 9.8 m/s^2. This is due to the acceleration due to gravity, which acts in the downward direction. Therefore, the correct answer is a) 9.8 m/s^2.

1c. The vertical acceleration of a projectile is 9.8 m/s^2. This is the same as the downward acceleration due to gravity. Therefore, the correct answer is a) 9.8 m/s^2.

2. Choose the right answer for each matching case below:
2a. The rate of change of velocity is acceleration. Acceleration is defined as the rate of change of velocity with respect to time. Therefore, the correct answer is d) acceleration.

2b. The rate of change of anything is always with respect to time. Time is the standard measurement used for changes in various quantities. Therefore, the correct answer is c) time.

2c. The rate of change of displacement is velocity. Velocity is defined as the rate of change of displacement with respect to time. Therefore, the correct answer is a) velocity.

3. The units of speed are m/s. Speed is defined as the distance traveled per unit of time. Therefore, the correct answer is a) m/s.

4. The displacement of an airplane from its starting point is 200 km at 60 degrees NE. To find the easterly component, we need to use trigonometry. The easterly component can be found by multiplying the displacement by the cosine of the angle.

Easterly component = 200 km * cos(60 degrees)
Easterly component ≈ 200 km * 0.5
Easterly component ≈ 100 km.

Therefore, the correct answer is c) 100 km.

I hope this explanation helps you understand the reasoning behind each answer choice. If you have any further questions, feel free to ask!