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8th Grade > Physics > Flashcards

Physics Flashcards

1
Q

What is the formula for speed?

A

S= D/T (speed = distance divided by time)

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2
Q

What is the formula for velocity?

A

V= D/T (velocity = distance divided by time + direction)

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3
Q

What is acceleration?

A

A change in the velocity of an object

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4
Q

What is the formula for acceleration?

A

Delta V/Delta T (change in velocity over change in time)

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5
Q

What are the SI units for velocity?

A

m/s (meters per second)

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6
Q

What are the SI units for acceleration?

A

m/s2 (meters per second squared)

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7
Q

How do we determine the change (delta) of time and velocity for acceleration?

A

Vfinal-Vinitial over Tfinal-Tinitial

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8
Q

What is Newton’s 1st Law?

A

The Law of Inertia: An object in motion tends to stay in motion, and an object at rest tends to stay at rest

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9
Q

What is required to overcome the inertia of an object?

A

an outside force

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10
Q

What is Newton’s 2nd Law?

A

The force/mass/acceleration relationship: the acceleration of an object is directly related to the force applied to an object and inversely related to the mass of the object

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11
Q

You’re pulling a wagon. Suddenly, the mass of the wagon is 5 times greater. The force you’re applying to the wagon is unchanged. What happens to the acceleration of the wagon?

A

It will decelerate (slow down)

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12
Q

What is Newton’s 3rd Law?

A

For every action (or force), there is an equal and opposite reaction (or reactive force).

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13
Q

If every force has an equal reactive force, how does anything move?

A

Because of the relationship WITHIN systems. We don’t calculate the force and opposing force at the same time; we only look at the forces that affect one object at a time.

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14
Q

What is the opposite force to gravity called?

A

the normal force

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15
Q

What is the difference between potential and kinetic energy?

A

potential energy is the possible energy of an object, kinetic energy is the energy of motion

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16
Q

What is the formula for kinetic energy?

A

Ke=1/2mv2 (Kinetic energy = 1/2 of object’s mass times velocity squared)

17
Q

What is work?

A

Force x Distance (measured in Joules)

18
Q

What is power?

A

Work/Time (work divided by time, measured in watts or horsepower)

19
Q

What is friction?

A

Friction is the force that the surfaces of two objects exert on each OR the force that an environment exerts on an object’s surface

20
Q

What is gravity?

A

the universal attractive force between objects

21
Q

What direction does friction always move in the presence of motion?

A

In the opposite direction of the motion

22
Q

What is static friction?

A

the friction present in objects that aren’t moving

23
Q

Water and air moving against the surface of an object is an example of _________ friction.

A

fluid friction

24
Q

Circular objects have rolling friction, which requires less force to overcome. Why is that the case?

A

reduced surface area contact between the objects

25
Q

Why do we measure both weight and force in Newtons?

A

Because weight is the product of mass and the force that gravity exerted on that mass (1 kg x 9.8 m/s2 = 9.8 N of weight)

26
Q

What is terminal velocity?

A

The final velocity of a falling object when it can no longer accelerate.

27
Q

What is elastic potential?

A

the ability of a material to compress or stretch under force and return to its original shape

28
Q

What is the formula for elastic potential?

A

W=Fs (Elastic potential = Force x Distance of Displacement)

29
Q

What is the restorative force?

A

The force exerted by a stretched or compressed material as it returns to its original state

30
Q

What’s the Zeroth Law of Thermodynamics?

A

If two systems are in equilibrium with a third system, then the first two are in equilibrium with each other.

31
Q

What’s the 1st Law of Thermodynamics?

A

Energy, including heat energy, cannot be created or destroyed

32
Q

What’s the 2nd Law of Thermodynamics?

A

The entropy or disorder of a system will always increase, not decrease

33
Q

What’s the 3rd Law of Thermodynamics?

A

The entropy of a perfect crystal at a temperature of absolute zero will be zero.

34
Q

According to the 2nd Law, does heat move from hot systems to cold systems, or cold systems to hot systems?

A

Heat moves from hot systems to cold systems to seek equilibrium

35
Q

Conduction, convection, and radiation are examples of what?

A

Transfers of thermal energy

8th Grade (4 decks)

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