midterm 1 Flashcards

1
Q

Which of the following statements best represents Newton’s first law of motion?

A

Every object at rest, or in uniform motion, will remain in that state of motion unless compelled to do otherwise by forces acting upon it.

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2
Q

If an object is in uniform motion then the object will have a constant speed and direction.

A

True

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3
Q

Which of the following statements is true?

A

The mass of an object is always the same, but the weight of an object changes based on the acceleration of gravity acting on the object.

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4
Q

What are the units for distance, speed, and acceleration, respectively?

A

m, m/s, m/s2

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5
Q

If there were no air friction (a vacuum), and if a feather and a wrench were dropped from the same height at the same time they would hit the ground at different times.

A

False

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6
Q

What is the acceleration due to gravity of all objects on Earth?

A

9.8 m/s2,
32 feet/sec2,
22 miles/hour every second

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7
Q

If there was a green and red ball located at the same height. If the red ball was shot horizontally and the green ball was dropped which ball would hit the ground first?

A

Both balls would hit the ground at the same time

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8
Q

If a ball was thrown in the air, what is the acceleration of the ball the moment it reaches its maximum height and zero speed?

A

9.8 m/s2

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9
Q

What law of motion describes why it is easier to accelerate objects with little mass?

A

Newton’s 2nd law of motion

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10
Q

If someone was in outer space with no other objects nearby, and they threw a ball. What would happen to the ball?

A

The ball would go at the same speed and direction forever.

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11
Q

What would happen if you had two charges and you brought them close together?

A

The charges would attract one another if they were opposite charges and repel one another if they were the same charges.

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12
Q

All electric currents create magnetic fields.

A

true

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13
Q

Which of the following scientists came up with the idea for positive and negative charges?

A

Benjamin Franklin

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14
Q

What experiment was used to determine the charge of an electron?

A

Oil drop experiment

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15
Q

What type of electricity is used in our homes, and what type of electricity is used to charge our batteries? (Hint look up how cellphone chargers work)

A

Alternating current is used in our homes and direct current is used to charge our batteries.

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16
Q

A generator is a set of magnets turning inside coiled wires. As a turbine moves the generator the magnetic field changes within the coils causing an electric current or voltage.

A

true

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17
Q

A speaker is one example of an electromagnet.

A

true

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18
Q

If you were standing on a scale in a stopped elevator, what would happen to the your weight reading on the scale if the elevator started moving up?

A

Weight more than at rest

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19
Q

When a falling object experiences terminal velocity it stops accelerating, and moves at a constant speed.

A

true

20
Q

What effects air friction for any object?

A

Surface Area

Speed

21
Q

What are Newton’s three laws of motion? Can you identify them and apply them in everyday situations?

A
  1. Every object at rest, or in uniform motion will remain in that state of motion unless compelled to do otherwise by forces acting upon it. Qualitative.
  2. force = mass x acceleration. Quantitative. If you double the force on an object without changing its mass, the acceleration doubles.
  3. forces occur when two things interact with each other. The two resulting forces have the same strength and act exactly in opposite directions.
22
Q

What is the acceleration due to gravity on Earth?

A

9.8 m/s^2

23
Q

What is the acceleration due to an object thrown in the air?

A

same as gravity on earth just minus initial speed

24
Q

What is mass? How are mass and weight related?

A

Mass-the characteristic of a body which determines how much it accelerates when a force is applied.
Weight- a measure of the force of gravity on a particular mass

25
Q

What will hit the ground faster a heavy or a light object in a vacuum?

A

same time

26
Q

If an object is given a horizontal force will it hit the ground sooner than another object dropped straight down at the same time? (Dropping a bullet vs. shooting a bullet)

A

same time

27
Q

How does riding in an elevator affect your weight? When will you weigh more, less or the same?

A

weigh less down, weigh more up

28
Q

If I tell you the acceleration of an object starting at rest could you tell me the velocity after a specific amount of time?

A

a change in an objects velocity is acceleratoin.

29
Q

If I tell you the constant speed of an object could you tell me how far it traveled in a specific amount of time?

A

yes

30
Q

If two pieces of tape are brought near one another and they are attracted or they are repelled what would cause the attraction or repulsion?

A

electrification, electro-magnetic. positively and negatively charged ions. ELECTRIC FORCE LAW. similar charges repel and dissimilar attract.

31
Q

Why did the pie tins fly off the Van de Graaff generator?

A

because they had positive charges to repel them

32
Q

What is the electrical model of matter? When there is an electric current, what always moves and what always stays in the same location?

A

Electrical model of matter is what it is made of. lightning pic. protons positive and electrons negative. electrons move while protons stick.

33
Q

What would happen if I had two magnets and I brought them close together?

A

stick or repel

34
Q

How is electricity generated all over the world?

A

because it is a giant magnet. electromechanical generators. electromagnetic induction.

35
Q

How did J.J. Thomson discover the electron?

A

tube, metal plates in sealed ends, evacuated tube, injected small gas into it. connected battery, beam appeared.

36
Q

How did Millikan discover the charge of the electron?

A

oil drop experiments. through a charged plate.

37
Q

How can a magnet lose their magnetism?

A

heat and feromagnetic

38
Q

How can you generate magnetism using electricity?

A

current flows through coil. iron bar with electrical current

39
Q

If I have two objects with a force of F, mass M and m, separated by a distance d. What would happen to the force F if I separated the distance by 5d? ( Solve for the new force in terms of the original force. )

A

k

40
Q

What is terminal velocity and what causes it?

A

constant velocity it can go and gravity. so when opposing force equals gravity force. no acceleration

41
Q

What will happen if you change a magnetic field?

A

it’ll switch fields

42
Q

What is a transformer used for? What type of electricity does it work on and what type does it not work on?

A

magnetic flux fluctuation going through wire current. DC dont work and AC work.

43
Q

If I show you a plot, can you distinguish alternating current from direct current?

A

direct current is a steady flow of electrons in one direction, typically though a wire. AC is a current of electrons that changes direction of flow.

44
Q

In your house where would you find alternating current, direct current, and static electricity respectively?

A

Ac used in home, battery charges is dc, and static, carpet is static

45
Q

What type of electricity is more efficient AC or DC?

A

AC

46
Q

What is the most common source of direct current?

A

batteries