Unit 2 - Forces

Question 1

Name 5 forces?

Answer 1

1. Gravity
2. Friction
3. Thrust
4. Reaction
5. Resistance

Question 2

What can forces do?

Answer 2

• Puush
• Pull
• Turn
• Change
• Twist

The direction of an object

Question 3

What unit do forces use?

Answer 3

Newtons

Question 4

If an unbalanced force acts upon an object, what will change?

Answer 4

It’s motion

Question 5

If no resultant force acts upon an object, what will happen to the object?

Answer 5

The object will either remain** stationary** or **continue moving **at a constant velocity

Question 6

Veloctiy

Answer 6

Speed in a given direction

Question 7

Resultant Force

Answer 7

The overall force on an object

Question 8

What’s the equation for force?

Answer 8

Force = mass x acceleration

Question 9

What does every reaction have?

Answer 9

An equal and opposite reaction

Question 11

What is the equation for Velocity?

Answer 11

Velocity = distance ÷ time

Question 12

What is the equation for acceleration?

Answer 12

Acceleration = (final velocity - start velocity) ÷ time

Question 13

What is the equation for weight?

Answer 13

Weight = mass x gravitational field strength

Question 14

Thinking time

Answer 14

The time take or an individual to decide weather to stop or not

Question 15

Thinking Distance

Answer 15

The distance moved during the time when you are reacting to a hazard

Question 16

Braking Time

Answer 16

The time for the car to slow down

Question 17

Braking distance

Answer 17

The distance travelled whilst braking

Question 18

Factors affecting thinking distance?

Answer 18

• Tiredness
• Alcohol
• Drugs
• Distractions eg loud music, phone

Question 19

Factors affecting braking distance?

Answer 19

• How worn the brakes are
• Tyres
• Surface of the road
• Mass of the vehicle
• Aerodynamics

Question 20

What is the Overall Stopping Distance?

Answer 20

The thinking distance and the braking distance added together

Question 21

Air resistance

Answer 21

A force due to air that is acting to oppose the motion of an object

Question 22

Factors affecting the size of air resistance?

Answer 22

• Surface area
• Speed of an object

Question 23

Regenetarive braking

Answer 23

An energy recovery mechanism which slows a vehicle or object down by converting its kinetic energy into another form which can be stored.

Question 24

Uses of Regenetarive braking?

Answer 24

• Trains
• KERS (kinetic energy recover systems) in formula 1

Question 25

Problems with regenetarive braking?

Answer 25

* Makes turning harder * Less predictable when turning * Cars still need friction

Question 26

Equation for work done?

Answer 26

Work done = energy transferred **Work done = force x distance moved ** (in the direction of the force)

Question 27

Name 4 ways you can reduce frictionq

Answer 27

* **Lubrication** (with oil, this means the surfaces no longer rub directly on each other, but slide past on a layer of oil) * **Air** (eg ice hockey, there's no friction to slow it down) * **Ball/roller bearings** (where balls or rollers allow the surface to move easily without actually touching each other) * **Using special materials** (eg Teflon, which have a very low co-efficiant of friction and this slide easily)