Forces

Question 1

adefine force

Answer 1

a push or pull that acts on an object due to it’s interaction with another object.

Question 2

what are the factors of a vector?

Answer 2

both have a magnitude and a direction

Question 3

give examples of contact forces

(3 marker)

Answer 3

• friction
• air resistance
• tension

Question 4

give examples of non-contact forces

(3 marker)

Answer 4

• magnetic force
• gravity
• electrostatic force

Question 4

give examples of non-contact forces

(3 marker)

Answer 4

• magnetic force
• gravity
• electrostatic force

Question 5

what are the factors of a scalar quantity?

Answer 5

it only has a magnitude

Question 6

examples of scalar quantities

(4 marker)

Answer 6

• speed
• distance
• mass
• time

Question 7

examples of vector quantities

(4 marker)

Answer 7

• velocity
• displacement
• force
• acceleration

Question 8

what are the forces acting on an object in a free body diagram?

Answer 8

• weight
• drag
• thrust
• lift

Question 9

what happens to a spring when a force is applied?

(3 marker)

Answer 9

• compressed
• bends
• stretches

Question 9

what are the two types of deformation?

Answer 9

• elastic deformation
• inelastic deformation

Question 10

elastic practical

Answer 10

• place the spring upright attached
• there would be a little extension since it’s weight would extend it
• add weights and measure the increase in length
• the mass and extension is directly proportional
• the force and extension is direcly proportional

Question 11

graph for elasticity

Answer 11

• the straight line would go from the origin suggesting force and extension are directly proportional
• this would all be elastic deformation (once the mass is removed it will return to normal)
• however once it reaches it’s limit, it will be permanently deformed.

Question 12

what is it called when it reaches the point of inelastic deformation?

Answer 12

limit of proportionality or elastic limit

Question 12

what is it called when it reaches the point of inelastic deformation?

Answer 12

limit of proportionality or elastic limit

Question 13

equations for elasticity

Answer 13

• F = k e
• Ek = 1/2 k e^2

Question 14

define deformation

Answer 14

the change in shape
1. length
2. cross sectional area

Question 15

define moment

Answer 15

the rotation or turning effect of a force

Question 15

equation for moment

Answer 15

M = F x d

Question 16

unit for moment

Answer 16

Newton metre (Nm)

Question 17

what is the rule for moments?

Answer 17

the sum of the total anticlockwise moment is equal to the sum of the total clockwise moment.

Question 18

what is the effect of a smaller object on moment

Answer 18

the smaller the object, the larger the force needed since it is applied closer to the point.

Question 19

what is the function of a lever?

Answer 19

transmits the turning effect of a force

Question 20

gears

Answer 20

• the wheels turn in opposite ways
• the second wheel is 2x bigger
• therefore the turning effect is also 2x bigger on the second wheel

Question 21

how is pressure created in gas?

Answer 21

* the particles collide with eachother and the wall * as they collide they apply a force

Question 22

why do particles colliding perpendicular generate more pressure than particles colliding at an angle?

Answer 22

* at perpendicular to the surface, all the force is exerted onto the wall and increases the pressure. * particles colliding at angles dont exert all the force onto the wall, producing less pressure.

Question 22

why do particles colliding perpendicular generate more pressure than particles colliding at an angle?

Answer 22

* at perpendicular to the surface, all the force is exerted onto the wall and increases the pressure. * particles colliding at angles dont exert all the force onto the wall, producing less pressure.

Question 23

equations for pressure

Answer 23

* p = F/A * p = h p g

Question 24

upthrust

Answer 24

* water particles around the box will collide with all sides of the surface * since the bottom surface of the box is deeper there would be a larger upwards force. * this is called upthrust.

Question 25

what happens if the weight is larger than the object?

Answer 25

the object will sink

Question 26

what happens if the upthrust is larger than the weight?

Answer 26

the object floats.

Question 27

where is the density highest in the atmosphere?

Answer 27

the density is highest when its closest to the earth's surface

Question 28

what happens as the altitude increases? | (3 marker)

Answer 28

* there is less pressure and density with the higher the altitude * so the number of particles colliding with the surface decreases * there is more acceleration sinced there are no air particles

Question 29

define atmospheric pressure

Answer 29

the air pressure created by collision between air particles and the surface

Question 30

what happens if there are more gas particles? | (2 marker)

Answer 30

* the greater the number of gas particles, the higher the pressure, so more frequent collisions * p = F/A

Question 31

what happens if there are more gas particles? | (2 marker)

Answer 31

* the greater the number of gas particles, the higher the pressure, so more frequent collisions * p = F/A

Question 32

equations for acceleration

Answer 32

* a = change in velocity/time * 2 a s = v^2 - u^2

Question 33

what is acceleration measured in?

Answer 33

m/s^2

Question 34

what does the gradient of a distance/time graph tell you?

Answer 34

the speed of the object

Question 35

what does a flat line on a distance/ time graph tell you? | (2 marker)

Answer 35

* the object is stationary * this is because the gradient is 0 meaning the speed must also be 0.

Question 36

what does an increasing gradient/steeper line show?

Answer 36

acceleration

Question 37

what does a decreasing gradient show?

Answer 37

deceleration

Question 38

what does the grdient tell you on a velocity/time graph?

Answer 38

the acceleration

Question 39

what is the constant positive gradient?

Answer 39

acceleration

Question 40

what is the constant negative acceleration?

Answer 40

decelaration

Question 41

what do flat lines on a velocity time graph tell you?

Answer 41

the velocity is constant and there is no acceleration

Question 42

what does a steeper gradient tell you?

Answer 42

increase in acceleratiom

Question 43

define terminal velocity

Answer 43

when velocity is constant

Question 44

define stopping distance

Answer 44

the minimum distance required to stop a vehicle in an emergency

Question 45

equation for stopping distance

Answer 45

thinking distance+ braking distance

Question 46

what affects the thinking distance?

Answer 46

speed of the vehicle reaction time

Question 47

what increases the reaction time in stopping distance?

Answer 47

tired drunk drugs distracted

Question 48

what factors affect the braking distance?

Answer 48

condition of the brakes speed + mass of car condition of roads