Chapter 5: Forces

Newtons

________ first law says that a resultant force is needed to make something start moving, speed up or slow down.

Gravity

________ attracts all masses, but you only notice it when one of the masses is really big, like a planet.

Weight

________ is the force acting on an object due to gravity, the pull of gravitational force on the object.

steady speed

To travel at a(n) ________, the driving force needs to balance the frictional forces.

Levers

________ increase the distance from the pivot at which the force is applied.

Free body

________ diagrams show all the forces acting on an object.

collision

Each ________ is an events where the momentum of each ball changes, but the overall momentum stays the same.

upthrust

The ________ is equal to the weight of fluid that has been displaced by the object.

Fluids

________ are substances than can flow because their particles are able to move around.

terminal velocity

However, on Earth, air resistance causes things to fall at different speed, and the ________ of any object is determined by its drag in comparison to its weight.

Vectors

________ are usually represented by an arrow- the length of the arrow shows the magnitude and the direction of the arrow shows the direction of the quantity.

Curves

________ represent acceleration or deceleration.

Distance

________ is Scalar, Displacement is a Vector.

Momentum

________ is mainly about how much ‘ oomph an object has.

Velocity

________ is speed in a given direction.

curve

A(n) ________ means changing acceleration.

Gears

________ are circular discs with ‘ teeth around their edges.

Displacement

________ is a vector quantity.

Flat sections

________ represents travelling at a steady speed.

event

If the momentum before a(n) ________ is zero, then the momentum after is zero.

Mass

________ is just the amount of stuff in an object.

emergency

In a(n) ________, a driver may perform a(n) ________ stop.

Acceleration

________ is definitely not the same as velocity or speed.

reaction time

Where the THINKING DISTANCE is how fast the car travels during the drivers ________.

overall force

A resultant force is the ________ on a point or object.

Gravitational force

________ is the force of attraction between masses.

Distance travelled

________= speed x time.

Atmospheric pressure

________ is created on a surface by air molecules colliding with the surface.

Inertial mass

________ can be found using Newtons Second Law of F= ma.

non zero resultant force

A(n) ________ will always produce acceleration in the direction of the force.

atmosphere

The ________ is a layer of air that surrounds Earth.

Uniform acceleration

________ means a constant acceleration.

Pressure

________ is force per unit area, so this means the particles exert a(n) ________.

smaller distance

Pushing at any other angle means a(n) ________, and so a smaller moment.

Wind speed

________ can be affected by things like temperature, atmospheric pressure and if there are any large buildings or structures nearby.

Terminal velocity

________ depends on shape and area.

curve

A steepening ________ means its speeding up (increasing gradient)

Levers

________ make it easier for us to do work.

Mass

________ is not a force, and is measured in kilograms with a(n) ________ balance.

Gears

________ transmit rotational effects.

non zero resultant force

The velocity will only change if theres a(n) ________ actin on the object.

gravitational force

The sun and the earth are attracted to each other by the ________.

Acceleration

________ is the change in velocity in a certain amount of time.

Some physical quantities only have magnitude and no direction, these are called scalar quantities

speed, distance, mass, temperature, time, etc

You can find out how much work has been done using

W=Fs

This acceleration can take five different forms

starting, stopping, speeding up, slowing down and changing direction

As long as a spring is not stretched past its limit of proportionality, the work done in stretching a spring can be found using

Ee=1/2ke2

Typical car barking distances are

14m at 30mph, 55mm at 60mph and 75m at 70mph

Before

The red ball is stationary, so it has zero momentum

After

The white ball hits the red ball, causing it to move

This is why cars are designed to slow people down over a longer time when they have a crash

the longer it takes for a change in momentum, the smaller the rate if change in momentum, and so the smaller the force