Download DYN.A – Original Assignment Name: Speed and Velocity Concepts

DYN.A – Original Assignment
Name:
Speed and Velocity
Concepts
Review:
1. A quantity that is fully described by magnitude alone is a ___________ quantity. A quantity that is
fully described by both magnitude and direction, is a ___________ quantity.
a. scalar, vector
b. vector, scalar
2.
Speed is a ____________ quantity. Velocity is a ____________ quantity.
a. scalar, vector
b. vector, scalar
c. scalar, scalar
d. vector, vector
3.
State the equation for calculating the average speed of an object:
Circular Motion:
4. An object that moves uniformly in a circle can have a constant ___________________ but a changing
___________________.
a. speed, velocity
b. velocity, speed
5.
The direction of a velocity vector is always ______. Circle all that apply.
a. in the same direction as the net force that acts upon it
b. in the opposite direction as the net force that acts upon it
c. in the same direction as the object is moving
d. in the opposite direction as the object is moving
e. ... none of these!
6.
True or False:
The direction of the velocity vector of an object at a given instant in time depends on
whether the object is speeding up or slowing down.
7.
For an object moving in uniform circular motion, the velocity vector is directed _____.
a. radially inwards towards the center of the circle
b. radially outwards away from the center of the circle
c. in the direction of the tangent line drawn to the circle at the object's location
8.
Use your average speed equation to determine the speed of ... . (Given: Circumference = 2•PI•R)
a. ... a rider on a carousel ride that makes a complete revolution around the circle (diameter = 21.2meter) in 17.3 seconds. PSYW
b. ... your clothes that are plastered to the wall of the washing machine during the spin cycle. The
clothes make a complete revolution around a 61.9-cm diameter circle in 0.285 seconds. PSYW
9.
A roller coaster car is traveling over the crest of a hill and is at the location
shown. A side view is shown at the right. Draw an arrow on the diagram
to indicate the direction of the velocity vector.
Academic Physics 2013 – Anderson HS
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DYN.A – Original Assignment
Name:
Calculations
1. An object is spun around in circular motion such that it completes 100 cycles in 25 s.
What is the period of its rotation?
2. An object completes 2500 cycles in 25 s.
What is the period of its rotation?
3. An object completes 10 cycles in 50 s.
What is the period of its rotation?
4. A 5.0 kg object is spun around in a circle of radius 1.0 m with a period of 4.0s.
What is its velocity?
5. A 15.0 kg mass is spun in a circle of radius 5.0 m with a period of 0.04 s
What is its velocity?
6. A 0.5 kg object is spun around in a circle of radius 2.0 m with a period of 10.0s.
What is its velocity?
7.
During their physics field trip to the amusement park, Tyler and Maria took a rider on the Whirligig.
The Whirligig ride consists of long swings which spin in a circle at relatively high speeds. As part of
their lab, Tyler and Maria estimate that the riders travel through a circle with a radius of 6.5 m and
make one turn every 5.8 seconds. Determine the speed of the riders on the Whirligig.
8.
In the display window of the toy store at the local mall, a battery-powered plane is suspended from
a string and flying in a horizontal circle. The 631-gram plane makes a complete circle every 2.15
seconds. The radius of the circle is 0.950 m. Determine the velocity.
9.
A boy is whirling a rock attached to a string overhead in a horizontal circle. The rock makes a
complete loop in 0.50 s and the string is 0.60 m long. Find the speed of the rock
10. A 2500 kg roller-coaster completes a loop of radius 16 m in 3.00 s. Determine the speed of the
coaster.
11. A manufacturer of CD-ROM drives claims that the player can spin the disc as frequently as
1200 revolutions per minute. If spinning at this rate, what is the speed of the outer row of
data on the disc; this row is located 5.6 cm from the center of the disc?
Academic Physics 2013 – Anderson HS
Page 2
DYN.A – Original Assignment
Name:
Concepts - Answers
Review:
1. A quantity that is fully described by magnitude alone is a ___scalar___ quantity. A quantity that is
fully described by both magnitude and direction, is a ___vector___ quantity.
a. scalar, vector
b. vector, scalar
2.
3.
Speed is a __scalar__ quantity. Velocity is a __vector__ quantity.
a. scalar, vector
b. vector, scalar
c. scalar, scalar
d. vector, vector
State the equation for calculating the average speed of an object:
average speed = distance/time
or
v = d/t
For circles: v = Circumference/Period
Circular Motion:
4. An object that moves uniformly in a circle can have a constant ___speed___ but a changing
___velocity___.
a. speed, velocity
b. velocity, speed
5.
The direction of a velocity vector is always ______. Circle all that apply.
a. in the same direction as the net force that acts upon it
b. in the opposite direction as the net force that acts upon it
c. in the same direction as the object is moving
d. in the opposite direction as the object is moving
e. ... none of these!
6.
True or False:
Answer: C
The direction of the velocity vector of an object at a given instant in time depends on
whether the object is speeding up or slowing down.
False. Whether speeding up or slowing down, velocity is always in the direction of motion.
7.
For an object moving in uniform circular motion, the velocity vector is directed _____. Answer: C
a. radially inwards towards the center of the circle
b. radially outwards away from the center of the circle
c. in the direction of the tangent line drawn to the circle at the object's location
8.
Use your average speed equation to determine the speed of ... . (Given: Circumference = 2•π•R)
a. ... a rider on a carousel ride that makes a complete revolution around the circle (diameter = 21.2meter) in 17.3 seconds. PSYW
v = d/t = 2•π•R/T where R is the radius (10.6 m) and T is the period (17.3 s).
v = 2•π•(10.6 m)/(17.3 s) = 3.85 m/s
b. ... your clothes that are plastered to the wall of the washing machine during the spin cycle. The
clothes make a complete revolution around a 61.9-cm diameter circle in 0.285 seconds. PSYW
v = d/t = 2•π•R/T where R is the radius (0.3095 m) and T is the period (0.285 s).
v = 2•π•(0.3095 m)/(0.285 s) = 6.82 m/s
9.
A roller coaster car is traveling over the crest of a hill and is at the location
shown. A side view is shown at the right. Draw an arrow on the diagram
to indicate the direction of the velocity vector.
The arrow should be directed tangent to the circular path.
Academic Physics 2013 – Anderson HS
Page 3
DYN.A – Original Assignment
Name:
Calculations – Answers
1.
2.
3.
4.
5.
6.
7.
8.
0.25 s
.01 s
5s
1.6m/s
785 m/s
1.257 m/s
7.0 m/s
2.78 m/s
9.
10.
11. 7.0 x 102 cm/s or 7.0
m/s
Academic Physics 2013 – Anderson HS
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