Mechanics

Front 1

how can you find the distance traveled from a speed/time graph?

Back 1

The distance traveled is the WHOLE area under a speed time graph

Front 2

What do vectors have that scalars don't

Back 2

Vectors have size AND direction
scalars only have size

Front 3

Example of vector

Back 3

velocity, acceleration, force

Front 4

What is the resultant force when an object moves at a constant speed?

Back 4

Zero

Front 5

In what direction does a support fore act relative to the surface the object is on?

Back 5

A support force stops something falling and always acts Perpendicular to the surface

Front 6

Which way does gravity act from a surface

Back 6

Straight down

Front 7

What is hooks law

Back 7

The more you pull something the more it stretches

F= -Kx

Front 8

In hooks law F= -Kx, what is the k value?

Back 8

The K is the stiffness of the spring measured in Nm-1

The higher the value of k the harder to stretch or compress

Front 9

In hooks law F=-kx what is the x value

Back 9

the extension of the spring

Front 10

What is the difference between mass and weight

Back 10

Mass depends on the amount of matter in the object measured in Kg

Weight is the force of gravity acting on the object, measured in N

Front 11

How do you convert ass to weight

Back 11

multiply by 9.8

Front 12

How do you convert km/h to ms-1

Back 12

multiply by 3.6

Front 13

What is newtons first law

Back 13

"Things like to keep doing what they are doing"

Front 14

Newtons second law

Back 14

F=ma

Front 15

Newtons third law

Back 15

For every action there is an equal and opposite reaction force at the time of impact only

Front 16

What is torque

Back 16

A turning force around a pivot
T=force x distance of force from pivot

measure in Nm-1

can be clockwise or anti clockwise

Front 17

What is equilibrium

Back 17

Is when something in not accelerating in any direction. The clockwise fore = the anticlockwise force

Front 18

What do you have to do when calculating torque and there are two supports

Back 18

You have to make one the pivot by making the torque there 0

Front 19

When calculating torque you must remember that the weight of the object always..........................

Back 19

acts through the center of mass ( middle of object)

Front 20

What is momentum

Back 20

Momentum is the measure of how hard it is to stop something that is moving. Everything with velocity has momentum

P= mass x speed

Front 21

what are momentums units

Back 21

kgms-1

Front 22

I momentum a vector

Back 22

yes because it is dependent on velocity which is a vector involving direction

Front 23

Is momentum conserved

Back 23

momentum is always conserved as long as there are no outside forces acting. The p of a system before a collision or explosion = the p of the system after

Front 24

Elastic collisions

Back 24

when one object bounces off other. Both Ek and momentum conserved

Front 25

inelastic collisions

Back 25

when objects stick together and move off together. Only p is cinserved

Front 26

what is an explosion

Back 26

when things fly apart from central point.

Front 27

What must you always remember when dealing with explosion calculations

Back 27

The forces between the two objects are always equal and opposite, because total momentum must equal zero because this is what it was before the explosion

Front 28

What is impulse

Back 28

Impulse = force x change in time

Front 29

what is impulse the same as

Back 29

change in momentum, which is
change in p= mass x change in speed

Front 30

How does extending the time of a collision lessen the force?

Back 30

As impulse = force x change in time, and impulse is the same a change in momentum (Mass x change in speed) the greater the change in time the smaller the fore is. This is because the change in p will be constant as the mass of objects, and change in speed of them will be the same no matter the time for collision, so for the same change in p a greater time means the force must decrease

Front 31

what is the condition needed for work to be done

Back 31

For work to be done the object must more in the direction of the force

Front 32

What is projectile motion

Back 32

It is when an object moves through the air under the influence of gravity only

Front 33

a projectile accelerates at 9.8ms-1 in the vertical direction. How does it move in the horizontal direction?

Back 33

There are no accelerating forces in the horizontal direction when a projectile moves through the air therefore the horizontal speed is always constant.

Front 34

What is the shape of a projectile path

Back 34

parabolic, which means it is symmetrical

Front 35

When does the VERTICAL velocity of a projectile equal 0

Back 35

At the max height of flight. It still has horizontal velocity at max height of flight

Front 36

What is the total time of the flight of a projectile

Back 36

TWice the time taken to reach highest point

Front 37

What is the distance travelled horizontally in projectile called

Back 37

Range

Front 38

In circular motion what is the period

Back 38

time taken for one complete revolution

Front 39

Does an object traveling in a circular motion accelerate?

Back 39

Yes because it constantly changes direction

Front 40

For something to accelerate it must have a net force. What provides this net force in circular motion

Back 40

centripetal force which acts towards the center of the circle, therefore the object always accelerates towards the center of the circle . This acceleration is called centripetal acceleration

Front 41

When an object moves in a circular direction, why is its SPEED constant.

Back 41

Because the centripetal force causing the ball to accelerate acts at right angles to the direction of motion