a.) A hockey puck is observed to be sliding along a flat frictionless surface at
ID: 2055920 • Letter: A
Question
a.) A hockey puck is observed to be sliding along a flat frictionless surface at a speed of 1 cm/min. There is no net force acting on the puck. Assuming it doesn't smash into anything, how fast will the puck be going 30 min later?cm/min
b.) An object is accelerating. Which one of the following statements is true?
Gravity must be causing the object to accelerate.
The object must be changing directions.
The object must be slowing down.
There is a net force acting on the object.
The object must be speeding up.
c.) A 100 kg block weighs 220 lb on Earth. If the block were transported to a planetary body that had the same free fall acceleration (as compared to Earth), which one of the following would be true?
The block would have the same mass and a bigger weight.
The block would have the same mass and a smaller weight.
The block would have the same mass and the same weight.
The block would have the same weight and a bigger mass.
The block would have the same weight and a smaller mass.
d.) What does it mean (in physics) to say that a quantity is conserved?
It means it's being saved up.
It means that the quantity is not being used.
It means the total amount is zero.
It means the total amount never changes.
e.) At a certain point in time, the total energy of a closed system is observed to be 70 J. Which one of the following statements is true?
Eleven hours later the energy of the system is 70 J.
Some of the energy must be potential.
Five hours later the energy of the system is 140 J.
Ten hours later the energy of the system is 35 J.
All of the energy must be kinetic if the objects are moving.
f.) Which one of the following angular momentum vs. time graphs demonstrates conservation of angular momentum?
GRAPH I GRAPH II GRAPH III GRAPH IV GRAPH V GRAPH VI
GRAPH I
GRAPH II
GRAPH III
GRAPH IV
GRAPH V
GRAPH VI
g.) Which of the following statements are impossible? Choose all that apply.
The parked truck had 0 J of KE.
The scooter had 0 J of KE and 370 kg·m/s of momentum.
A ball moving in a circle had 780 N of net force acting on it.
A box had an acceleration of 0 m/s2 while a net force of 764 N acted on it.
Jack exerted 152 N of force due west on a cart. As a direct result, the cart exerted 152 N of force due west upon Jack.
A spoon exerts a smaller gravitational force upon Venus than Venus exerts upon it.
h.) A ball is being twirled in a circle as shown below. When the ball is in the pictured configuration, the string breaks. If we ignore gravity, which arrow best represents the path the ball will follow after the string breaks?
The picture below is a door as viewed from directly above. The black circle represents the hinges. Each arrow represents a force that is being applied to the door. Each force has the same magnitude. Use this diagram to answer the following three questions.
i.) Which forces shown have no lever arm? Choose all that apply.
A
B
C
D
E
F
G
H
j.) Which forces shown have a lever arm but create no torque? Choose all that apply.
A
B
C
D
E
F
G
H
k.) Which forces shown maximize the torque they create? Choose all that apply.
A
B
C
D
E
F
G
H
Explanation / Answer
a)No net force. => a = 0 Hence speed after 30min. = 1cm/min b)There is a net force acting on the object. c)The block would have the same mass and the same weight. d)It means the total amount never changes. e)Eleven hours later the energy of the system is 70 J. f) "NO GRAPHS" g) The scooter had 0 J of KE and 370 kg·m/s of momentum. A box had an acceleration of 0 m/s2 while a net force of 764 N acted on it. Jack exerted 152 N of force due west on a cart. As a direct result, the cart exerted 152 N of force due west upon Jack. A spoon exerts a smaller gravitational force upon Venus than Venus exerts upon it. h), (i), (j), (k) = "NO PICTURE!"
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