# Physics

1. Which statement below is true?
a. If a car is traveling eastward, its acceleration is eastward.
b. If a car's speed is decreasing, its acceleration must be negative.
c. If a particle is moving, it must have a non-zero acceleration.
d. A moving particle with constant acceleration can never stop and stay stopped.

2. A projectile is launched straight upwards at +45 m/s. Three seconds later, its velocity is approximately:
a. +75 m/s
b. +30 m/s
c. +15 m/s
d. 0 m/s

3. A ball is thrown straight up. At the top of its path its acceleration has a value (magnitude) of __________.
a. 0 m/s/s.

4. An object is shot vertically upward into the air with a positive initial velocity. Which of the following correctly describes
the velocity and acceleration of the object at its maximum elevation?
Velocity Acceleration
A) Positive Positive
B) Zero Zero
C) Negative Negative
D) Zero Negative
E) Positive Negative

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3. 👁 353
1. Hey, I already took 8:01, freshman physics.
I am here to help if you get stuck, not to do the problems for you. These are very basic questions

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2. Sorry,
1. c
2. d
3. a
4. b

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3. 1. c is not correct. a particle moving at constant velocity has no acceleration.
However how could a particle with constant acceleration stay stopped?

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4. 2. 45 - 10*3 = 15 which is c

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5. 3. The acceleration of g = -9.81 m/s^2 is CONSTANT, even if the speed is zero !

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6. 4. It is stopped, but the acceleration is STILL -9.81 m/s^2
from the time it is launched until it hits the ground or something.

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7. 1. a

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8. 1 d

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