Chapter 1- Momentum And Energy

Question 1

Impulse eq

Answer 1

Impulse = force x time

Question 2

Impulse unit

Answer 2

Newton seconds

N s

Question 3

Impulse =

Answer 3

Change in momentum

Question 4

Force =

Answer 4

Rate of change of momentum

Question 5

Impulse shown on what type of graph

Answer 5

Force- time graphs

Impulse= area under the graph

Question 6

Car safety calculations

Answer 6

Change in momentum when car is brought to rest produces an impulse Ft.
If we increase the time then the force will decrease increasing the safety of the passengers (for same mv)

Question 7

Car safety precautions

Answer 7

Crumple zones
Seat belts
Air bags in front seats

Question 8

Collisions where kinetic energy is not conserved

Answer 8

In elastic

Question 9

Collisions where kinetic energy is conserved

Answer 9

Elastic

Question 10

Work done by a force eq

Answer 10

Work= force x distance

Question 11

Gravitational potential energy eq

Answer 11

mgh

Question 12

Elastic potential energy eq

Answer 12

1/2 kx^2

Question 13

Kinetic energy eq

Answer 13

1/2 mv^2

Question 14

Types of mechanical energy

Answer 14

• GPE
• KE
• EPE

Question 15

Mechanical energy sometimes appears to be lost to surroundings often as a result of…

Answer 15

Work done against contact friction or air resistance

Question 16

Thermal energy of the particles of the surroundings is also called?

Answer 16

Internal energy

Question 17

Principle of conservation of energy def

Answer 17

Energy can neither be created or destroyed: can only be transferred from one form to another

Question 18

Eq combining kinetic energy and momentum

Answer 18

p= ✔️2mEk

Ek= p^2 / 2m

Question 19

What is the speed of light in air

Answer 19

3 x10 ^8 m/s

Question 20

Electron volt def

Answer 20

The energy gained by a particle of unit electronic charge when accelerated through a pd of 1 volt

Question 21

1 eV = how many joules

Answer 21

1.6 x10^-19 J

Question 22

What can be different even if kinetic energies are the same?

Answer 22

Momenta

Question 23

Which type of diagram can be used to show loss of energy

Answer 23

Sankey diagram

Question 24

Momentum in two dimensions what must equal the total forward momentum

Answer 24

For momentum to be conserved, the total forward momentum must equal the momentum vector totals
(The sum of the resolved momenta)

Question 25

Force = the rate

Answer 25

Of change of momentum

Question 26

What is the difference in eq between force and instantaneous force

Answer 26

F= m 🔺v/ 🔺t

Or

F= m dv/dt

Question 27

Force equations the other way around

Answer 27

F= v 🔺m/ 🔺t

Or

F= v dm/dt

Question 28

Water cannons are widely used in…

Answer 28

Crowd control

Question 29

Alternative to

F= v 🔺m/ 🔺t

Answer 29

F = v^2 A ‘rho’

Question 30

Simplified jet engine (3 part)

Answer 30

1) takes in cold air
2) heats up this air
3) throws out hot air

Question 31

Doodlebugs bomb mechanics

Answer 31

Used all the fuel they carried by the end of the flight
Londoners could hear the engine cut out
Sudden silence meant a bomb was about to fall to the ground