Forces pt2 (Pressure, upthrust, velocity, Newtons 1st law) Flashcards

1
Q

what do pressure in fluids cause?

A

a force normal (at right angles) to any surface

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2
Q

the equation for the pressure of fluids

A

pressure = force/area

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3
Q

what does a liquid with high density mean?

A

means that it has more particles that are able you collide so the pressure is higher

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4
Q

Why does liquid pressure increase with depth?

A

because the weight of all the particles above adds to the pressure felt at that point

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5
Q

What does the pressure at a particular point in a column of liquid depend on?

A
  • the height of the column above the point
  • the density of liquid
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6
Q

The higher the column and the denser the liquid………. (3)

A
  • the greater the weight above the point
  • the greater the force on the surface at that point
  • the greater the pressure
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7
Q

the for the pressure of fluids in a column

A

pressure = height of column x density of liquid x gravitational field strength

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8
Q

How is atmospheric pressure created?

A

by air molecules colliding with the surface

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9
Q

the greater the altitude…

(why is this)

A

the less dense the atmosphere and the lower the atmospheric pressure

  • this is because there are fewer air molecules that are able to collide with the surface
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10
Q

What is upthrust?

A

the upward force exerted by a fluid on a submerged object

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11
Q

What happens when an object is submerged in liquid?

A

The pressure of the fluid exerts a force from every direction the bottom surface experiences a greater pressure than the top surface and this creates a resultant force upwards.

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12
Q

Why does an object float?

A

because the weight is equal to the upthrust

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13
Q

Why does an object sink?

A

because the weight is greater than the upthrust

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14
Q

What happens when an object is less dense than the liquid?

A
  • it will displace a volume of liquid greater than its own weight so it will rise to the surface
  • will float with some of the object remaining below the surface
  • displaces liquid of equal weight to the object
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15
Q

what happens when the object is denser than the surrounding liquid?

A

it cannot displace enough liquid to equal its own weight so it sinks

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16
Q

what is the size of upthrust equal to?

A

the weight of the liquid displaced

17
Q

When an object is travelling in circles…

A

-constantly changing direction = constantly changing velocity - accelerating even if travelling at a constant speed

18
Q

What is Newtons First law?

A

An object will remain in the same state of motion unless acted on by an external force

19
Q

Newtons First law: The velocity of an object will only change…

A

if there is a resultant force acting on is

20
Q

Newtons First law: A non-zero resultant force will always produce…

A

acceleration or deceleration in the direction of the force

21
Q

what is inertia

A

the tendency of objects to continue in their state of rest or of uniform motion

22
Q

What is the speed of walking?

A

1.5 m/s

23
Q

What is the speed of running?

A

3m/s

24
Q

What is the speed of cycling?

A

6 m/s

25
Q

What is the speed of sound?

A

330 m/s

26
Q

the equation for distance, speed and time

A

distance = speed x time