Corrections

Question 0

This is the formula for Kinetic Energy:

E = 1/2mv

True or False?

Answer 0

False. The equation for Kinetic Energy is E = 1/2mv^2

Question 1

What’s wrong with this equation:

KE = mv^2

Answer 1

The mass is not divided by 2.

It should be KE = 1/2mv^2

Question 2

List 4 factors decreasing road accidents

Answer 2

• seat belts
• airbags
• safer cars
• crumple zones, or;
• side-impact bars

Question 3

Seat belts prevent the…

Answer 3

Driver from hitting the steering wheel or windscreen

Question 4

How do you find the torque of a couple?

Answer 4

One of the forces times the PERPENDICULAR distance between the forces

Question 5

Why does strain have no unit?

Answer 5

It’s a ratio of two lengths

Question 6

When acceleration is constant…

Answer 6

Use the constant acceleration equations

Question 8

Define Ultimate Tensile Strength

Answer 8

Ultimate Tensile Strength is the breaking stress for material

Question 9

Force F acts on an object at angle Θ, an equation for this is W = FxCosΘ. Why not just W = Fx?

Answer 9

The COMPONENT of the force in the direction of the force is FCosΘ

Question 11

Force F acts on an object at angle Θ, give an equation for the work done, W

Answer 11

W = FxCosΘ

Question 12

What does the gradient of a displacement time graph represent?

Answer 12

Velocity

Question 13

A couple…

Answer 13

Is a pair of equal and parallel but opposite forces

Question 14

What is Young Modulus defined as?

Answer 14

Stress per strain, as long as elastic limit isn’t reached

Question 15

Define velocity

Answer 15

Velocity is the rate of change of displacement

Question 16

What are the conditions for equilibrium?

Answer 16

• all forces on the object equal zero

* net moment about any point is zero

Question 17

Seat belts decrease…

Answer 17

The impact force on the driver

Question 18

Airbags deflate…

Answer 18

Quickly to prevent whiplash

Question 19

What is a Brittle material?

Answer 19

A Brittle material breaks at its elastic limit, it has no plastic region

Question 20

Couples tend to produce…

Answer 20

Rotation

Question 21

Define the Joule

Answer 21

The work done when a force of 1N moves 1m in the direction of the net force

Question 21

What is the equation for Kinetic Energy?

Answer 21

KE = 1/2mv^2

Question 21

Other than deflating quickly to prevent whiplash, what other safety feature do Airbags feature?

Answer 21

Much wider area of bag reduces the pressure

Question 22

What is the constant acceleration equation without s?

Answer 22

v = u + at

Question 23

What is the constant acceleration equation without a?

Answer 23

s = (u+v)/2 x t

Question 24

What is the constant acceleration equation without v?

Answer 24

s = ut + 1/2at^2

Question 25

What is the constant acceleration equation without u?

Answer 25

s = vt - 1/2at^2

Question 26

What is the constant acceleration equation without t?

Answer 26

v^2 = u^2 + 2as

Question 27

An object travels two paths, one with and one without a slope, both have the same resistive force. Which will travel the furthest?

Answer 27

Journey down the slope, as there is a component of weight acting down. The net force is less, deceleration is smaller.

Question 28

What type of waves do satellite's use?

Answer 28

Radio or Microwave

Question 29

How do you determine the distance between a GPS device and satellite?

Answer 29

Delay time x c

Question 30

What do satellites use to locate GPS devices?

Answer 30

Trilateration, using spheres

Question 31

What is delay time?

Answer 31

The time taken for a signal to travel from the satellite to a receiving GPS device

Question 32

What is the relationship between drag and speed?

Answer 32

Drag is proportional to speed^2

Question 33

How to do you find stress?

Answer 33

force/area

Question 34

How do you find strain?

Answer 34

Length/extension

Question 35

What is the relationship between Young Modulus, strain and stress?

Answer 35

Young modulus = stress/strain

Question 36

What is Young Modulus measured in?

Answer 36

Pascals (Pa/Nm^-2)

Question 37

True or false: Kinetic energy is converted into heat energy

Answer 37

True

Question 38

True or false: gravitational potential energy is converted into heat energy/loss

Answer 38

False. GPE is converted to KE, then KE is converted to heat energy/loss

Question 39

Define work done

Answer 39

Force by distance moved in the direction of the force

Question 40

What does a straight gradient on a distance/time graph represent?

Answer 40

Constant speed

Question 41

True or false: Kinetic energy is converted into heat energy

Answer 41

True

Question 42

True or false: gravitational potential energy is converted into heat energy/loss

Answer 42

False. GPE is converted to KE, then KE is converted to heat energy/loss

Question 43

Define work done

Answer 43

Force by distance moved in the direction of the force

Question 44

What does a straight gradient on a distance/time graph represent?

Answer 44

Constant speed