P8 and P9

Question 1

What happens to energy when the system is changed

Answer 1

when the system is changed , there is a change of the way some or all the energy is stored

Question 2

Why is there no energy loss in a closed system ?

Answer 2

because there will be no influence outside of the energy transfer -100% efficiency

Question 3

Formula for work done

Answer 3

Work done = Force x Distance

Question 4

How can a mechanical process become wasteful

Answer 4

When 2 surfaces rub against each other , this is friction . this causes the heating of the 2 surfaces and unnecessary thermal energy is stored

Question 5

Formula for power

Answer 5

power(W)= Work done / time

Question 6

formula for efficiency

Answer 6

Useful energy / total energy

Question 7

Formula for GPE

Answer 7

Mass x gravity x change in height

Question 8

What are some factors affecting thinking and breaking distance ?

Answer 8

THINKING DISTANCE : tiredness
drugs

BRAKING DISTANCE : condition of breaks
icy roads / wet roads
mass of the car