P10 (Force And Motion)

Question 1

2 effects of gravity

Answer 1

• on planet surfaces it makes things fall

- gives everything a weight

Question 2

Mass

Answer 2

This is the amount of things inside an object

Question 3

Weight

Answer 3

• This is the force acting on an object due to gravity caused by the gravitational field
• can change depending on the strength of the gravitational field

Question 4

Centre of mass

Answer 4

The force acting from a single point, at the centre

Question 5

Weight (N)

Answer 5

Mass (kg) x gravitational field strength (N/Kg)

Question 6

If an object is equilibrium

Answer 6

If all the force acting on the object give a resultant force of 0

Question 7

3 ways energy transfers through forces

Answer 7

• stretching
• compressing
• bending

Question 8

What makes something ‘elastic’?

Answer 8

• If an object is elastically deformed it can go back to the original shape once the force is removed
• all energy is transferred to the elastic energy store

Question 9

What makes an object “inelastic”?

Answer 9

• does’t return to original shape after force is removed

- not all energy is transferred to elastic potential energy

Question 10

Force, Spring constant, Extension equation

Answer 10

Force(N) = SC(N/m) x Ext(m)

Question 11

Friction

Answer 11

• makes things stop if there is no force
• acts in opposite direction
• between 2 objects

Question 12

Drag

Answer 12

• resistance you get in either a gas or liquid

- keeping objects streamlined reduces drag as the fluid can flow easily across it

Question 13

Terminal velocity

Answer 13

• free falling objects accelerates as gravity stronger than frictional force
• eventually friction builds up and the two forces will be equal where it reaches a terminal velocity (constant speed)

Question 14

2 factors terminal velocity depend on

Answer 14

• shape

- area

Question 15

Newtons 1st law

Answer 15

• if the resultant force of a stationary object is 0, it will stay stationary
• if the resultant force of a moving object is 0, it will carry on moving at the same velocity

Question 16

Newton’s 2nd law

Answer 16

• larger resultant force, quicker the acceleration as they’re directly proportional
• large mass, accelerate less than a smaller mass at a constant resultant force

Question 17

Resultant force (N)

Answer 17

Acceleration(m/s^2) x Mass(Kg)

Question 18

Inetia

Answer 18

tendency for a motion to remain unchanged in objects at rest or moving (Newton’s 1st law)

Question 19

Inertia Mass

Answer 19

• how difficult it is to change the velocity of an object

- done by Force / acceleration finding the ratio

Question 20

Newtons 3rd Law

Answer 20

When two objects interact the forces exerted on each other are equal and opposite

Question 21

4 Stages of Newton’s second law practicle

Answer 21

1) Connect trolley to piece of string with the mass
2) Make a start line for the trolley to the light gate
3) release the pulley and measure the acceleration of the system from the light gate
4) repeat the experiment to find an average acceleration

Question 22

Stopping Distance =

Answer 22

Thinking distance + breaking distance

Question 23

2 factors your thinking distance is effected by

Answer 23

• speed

- reaction time

Question 24

4 things your braking distance is effected by

Answer 24

• speed
• weather/ road surface in ice conditions less friction
• condition of the tires
• quality of the breakes

Question 25

How do brakes work?

Answer 25

- brake pads pushed against wheels - causes friction and work to be done - kinetic to thermal energy - higher speeds= higher breaking force but can be dangerous

Question 26

What is reaction time + 4 factors affecting it?

Answer 26

- time taken between a stimulus and your reaction in response - tiredness, drugs, alcohol and distractions

Question 27

Why does speed effect braking distance more than thinking distance?

Answer 27

- thinking distance is linear and constant to the speed | - more work is done, as speed doubles the kinetic energy increases 4 fold (2^2)

Question 28

Momentum(kg m/s) =

Answer 28

Mass(kg) x velocity(m/s)

Question 29

Conservation of momentum

Answer 29

In a closed system the total momentum before the event is the same after the event

Question 30

Explain how momentum is passed

Answer 30

- with a stationary pool ball the momentum is 0 - as the moving pool ball collides with the stationary the momentum passed on is equal to the original momentum - the pool ball looses momentum drastically

Question 31

Force (N) = | - for momentum

Answer 31

Change momentum(kg m/s) / change time(s)

Question 32

3 car safety features

Answer 32

- crumple zones increase time for car to stop - seat belts stretching increase time for person to stop moving - air bags inflate to increase the time to stop by the compressed air