# Unit 1: Kinematics

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14 Νοε 2013 (πριν από 4 χρόνια και 7 μήνες)

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9
/5/13

AP Physics C

Ch 2
; 4.1
-
4.3; 10.1
-
10.3

Unit 1:
Kinematics

1.
How far does a
water balloon

that is released from rest fall between t = 4 and t = 5 sec.?

2. A test rocket is fired vertically upward from a
well. A catapult gives
it an initial speed of 80.0 m/s at

ground level. Its engines
then
fire

immediately

and it accelerates upward at 3.80 m/s
2

until it reaches an altitude of 1010 m. At that point its engines fail
,
and the rocket goes into free fall.
(For parts a
-
c, draw a dia
gram and write the general form of the appropriate equation; you do
not have to solve)

(a) How long is the rocket in motion above the ground?

(b) What is its maximum altitude?

(c) What is its velocity just before it collides with the Earth?

3. A marble rolls down a track as diagrammed to the right.

Sketch an x
-
t, v
-
t, & a
-
t graph of the marble’s motion on the axes below.

9
/5/13

AP Physics C

Ch 2
; 4.1
-
4.3; 10.1
-
10.3

Unit 1:
Kinematics

4
.
While
on a hike, you find an old well in the forest. Your friend asks how deep you think it is. You drop a rock from rest into the
well and time how long it takes for you to hear a splash.

(a) The sound of the splash is actually heard
2.4 s after

the rock is
re
leased from rest. How far below the top of the well is the
surface of the water? The speed of sound in air (at the ambient
temperature) is 336 m/s.

(Draw a diagram and write the general
form of the appropriate equation; you do not have to solve)

5.
Suppose that a ramp is tilted downward at angle of 20°. A ball rolls down it and leaves the bottom of the tilted ramp with a
speed of 1.5 m/s.

The bottom of the ramp is 0.90 m above the floor. Calculate how far it travels along the ground before it hits
the ground.

9
/5/13

AP Physics C

Ch 2
; 4.1
-
4.3; 10.1
-
10.3

Unit 1:
Kinematics

0

.50

1.0

-
.50

-
1.0

v(m/s)

t(s)

.2

.
4

.
6

.
8

1.0

1
.2

1.4

1.6

Questions 69
-

refer to the velocity vs. time graph shown above that represents the motion of a yo
-
yo undergoing a “Hop the
Fence” trick. Upward is positive.

6
. When is the yo
-
yo at the bottom of its motion? The top? How do you know?

7
. Plot a quantitatively correct position vs. time graph for
the entire motion.

8
. Plot a quantitatively correct acceleration vs time graph
for the entire motion.

9
. In the space belo
w, sketch a diagram for the yo
-
yo’s motion.

9
/5/13

AP Physics C

Ch 2
; 4.1
-
4.3; 10.1
-
10.3

Unit 1:
Kinematics

10
.
A person spinning on a turntable

with a radius of 0.5 m spins from rest according to the
following function, θ = 0.15t
2
.
Determine the angular acceleration. If a little bug is sitting half
-
way between the center and the outer edge, what are its angular
(or “rotational”)
velocity and linear (or “translational”) velocity?

11. A typical AP physics student accelerates 3 m/s
2

and can reach a top speed of around 7 m/s. Cheetahs can run at 60 mph. If I
gave you a head start of 80 meters from rest, and the cheetah was already running at top speed. How much time would it take
for
the cheetah to catch you?