Force, Energy And Momentum

Question 1

What is the difference between scalar and vector quantities

Answer 1

Scalars describe only a magnitude while Vectors describe magnitude and direction

Question 2

What are some examples of scalar quantities

Answer 2

Distance speed mass and temp

Question 3

What are some examples of vector quantities

Answer 3

Displacement velocity force/weight and acceleration

Question 4

How do you find the resultant force of two perpendicular forces

Answer 4

Use Pythagoras

Question 5

How do you find the direction of two perpendicular forces

Answer 5

Trigonometry

Question 6

What type of diagram should be drawn to show two forces that are not perpendicular

Answer 6

A scale drawing

Question 7

For an object to be in equilibrium the sum of all the forces acting on it should add up to what

Answer 7

0

Question 8

Does an object in equilibrium have a resultant force and what does that mean about the motion of the object

Answer 8

It has no resultant force so the object is either at rest or moving at a constant velocity

Question 9

What are the two ways of showing an object is at equilibrium

Answer 9

Adding the horizontal and vertical components of the forces acting on it showing they equal to 0
Or if there are 3 forces acting on it draw a scale diagram if the scale diagram forms a closed diagram then the object is in equilibrium

Question 10

What is the equation for a moment

Answer 10

Moment = force x perpendicular distance to line of action of the force from the point

Question 11

What is a couple

Answer 11

Is a pair of coplanar forces( forces that act in the same plane) where the two forces are equal in magnitude but act in opposite directions

Question 12

How do you find the moment of a couple

Answer 12

Moment of a couple = force x perpendicular distance between the lines of action of forces

Question 13

What does the principle of moments state

Answer 13

That for an object in equilibrium, the sum of the anti-clockwise moments about a pivot is equal to the sum of the clockwise moments

Question 14

What is the centre of mass of an object

Answer 14

Is when an object is balanced at a particular point this means at this point the object does not turn meaning all the weight on one side of the pivot is equal to the weight on the other side of the pivot

Question 15

What does it mean if an object is described as uniform

Answer 15

The centre of mass is exactly at its centre

Question 16

What is speed

Answer 16

How quickly an object is travelling

Question 17

What is displacement

Answer 17

The overall distance travelled from the starting position

Question 18

What is velocity

Answer 18

Rate of change of displacement

Question 19

what is acceleration

Answer 19

rate of change of velocity

Question 20

what is instantaneous velocity and how can it be found

Answer 20

is the velocity of an object at a specific point in time
it can be found from a displacement time graph by drawing a tangent to the graph at the specific time and calculating the gradient

Question 21

what is average velocity and how can it be found

Answer 21

is the velocity of an object over a specified time frame it can be found by dividing the final displacement by the time taken

Question 22

what is uniform acceleration

Answer 22

where the acceleration of an object is constant

Question 23

what do acceleration time graphs represent and what does the area under the graph equal

Answer 23

represents the change in acceleration over time and the area under the graph equals the change in velocity

Question 24

what do velocity time graphs represent and what does the gradient and area under the graph equal

Answer 24

represent the change in velocity over time and the gradient equals acceleration and the area under the graph equals displacement

Question 25

what do displacement time graphs represent and what does the gradient equal

Answer 25

shows the change in displacement and the gradient equals velocity

Question 26

what equations can you use when an object is moving at uniform acceleration

Answer 26

SUVAT's

Question 27

are the vertical and horizontal components of projectile motion dependent or independent

Answer 27

independent

Question 28

how do you calculate projectile motion

Answer 28

calculate horizontal and vertical components separately using the uniform acceleration formula

Question 29

what is free fall

Answer 29

where an object experiences an acceleration of g

Question 30

what is friction and what else is it known as

Answer 30

a forces which opposes the motion of an object and can be known as drag or air resistance

Question 31

when does the magnitude of air resistance increase

Answer 31

when the speed of the object increases

Question 32

what is lift and what it caused by

Answer 32

is an upwards force which acts on an object travelling in a fluid and is caused by the object creating a change in direction of fluid flow

Question 33

when does terminal speed occur

Answer 33

occurs where the frictional forces acting on an object and driving forces on an object and so there is no resultant force so no acceleration so the object travels at a constant speed

Question 34

what is an example of an object reaching terminal speed

Answer 34

- as they leave the plane they accelerate because their weight is greater than the air resistance - as the skydiver's speed increases, the magnitude of air resistance also increases - this continues until the force of weight and air resistance become equal, at which point terminal velocity is reached

Question 35

what does air resistance affect in projectile motion

Answer 35

the horizontal and vertical components as the max height is reached quicker and it doesn't travel as far or as high

Question 36

what is newtons first law

Answer 36

an object will remain at rest or travelling at a constant velocity until it experiences and external resultant force

Question 37

what is newtons second law

Answer 37

the acceleration of an object is proportional to the resultant force experienced by the object F = M A

Question 38

what is newtons third law

Answer 38

for each force experienced by an object the objects exerts an equal and opposite force

Question 39

what is momentum

Answer 39

is the product of mass and velocity of an object

Question 40

what is impulse

Answer 40

is the change in momentum

Question 41

what is force

Answer 41

the rate of change of momentum

Question 42

on a force time graph what is the area under the graph equal to

Answer 42

the the change in momentum

Question 43

what are the two types of collisions

Answer 43

elastic and inelastic

Question 44

what is an elastic collision

Answer 44

where both momentum and kinetic energy is conserved

Question 45

what is inelastic collision

Answer 45

where only momentum is conserved while the kinetic energy is converted into other forms

Question 46

what makes it an inelastic collision

Answer 46

when the object in a collision stick together after the collision

Question 47

what is work done

Answer 47

the force causing a motion multiplied by the distance travelled in the direction of the force

Question 48

what does the rate of doing work equal

Answer 48

the rate of energy transfer

Question 49

what is power

Answer 49

the rate of energy transfer

Question 50

what is the area of a force displacement graph equal to

Answer 50

work done

Question 51

what is efficiency

Answer 51

is a measure of how efficiently a system transfers energy

Question 52

what is the principle of conservation of energy

Answer 52

that energy cannot be created or destroyed but can be transferred from one form to another

Question 53

if the total energy is in a closed system does the energy stay constant

Answer 53

yes

Question 54

what is an example of conservation of energy

Answer 54

the thrower gives the ball kinetic energy therefor it moves upwards, however as it does the ball slows down because kinetic energy is being transferred to gravitational potential energy - eventually, all the kinetic energy is transferred to gravitational potential energy and the ball stops momentarily, after which the ball's gravitational potential energy is converted back into kinetic energy and the ball falls to the ground