Question

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

Answer 1

#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.