Equations 2

Question 1

Work Done (j)

Answer 1

Force applied(n) X Distance(m)

Question 2

Change in objects Gravitational Potential energy store (j)

Answer 2

Weight X Change of height

Question 3

Change of Gravitational potential energy store

Answer 3

Mass(kg) X Gravitiational Field Strength (N/Kg) X Change of height (m)

Question 4

Kenetic Energy (j)

Answer 4

1/2 X mass (kg) X Speed Squared (m/s Squared)

Question 5

Elastic Potential Energy (j)

Answer 5

1/2 X Spring Constant (N/m) X Extension Squared (m2)

Question 6

Effieciency

Answer 6

Total Input energy supplied to device

Question 7

Power (Watts)

Answer 7

Time taken for energy to be tranferred (s)

Question 8

Effiency in %

Answer 8

Useful power out
—————– (X100)
Total power out

Or

Useful energy transferred by the device
—————————————- (X100)
Total energy supplied to it

Question 9

Power wasted

Answer 9

Total power in - useful power out

Question 10

Energy transferred (joules)

Answer 10

Mass X Specific Heat Capacity (joule per kilogram) X Temperature change (degree celsius)

Question 11

Moment (newton metre) (nm)

Answer 11

Force X Perpendicular distance from the line of action of the force to the pivot (metres)

Question 12

Principle of moments

Answer 12

W1 d1 = W2 d2

Question 13

Speed (m/s)

Answer 13

Time taken

Question 14

Acceleration (m/s squared)

Answer 14

Time taken for the change(s)

Or

A = V - U
——
T

Question 15

Resultant force (n)

Answer 15

Mass (kg) X Acceleration (m/s squared)

Question 16

Weight (n)

Answer 16

Mass (kg) X Gravity Field Strength (n/kg)

Question 17

Stopping distance

Answer 17

Thinking +breaking

Question 18

Conservation of momentum

Answer 18

(Mass of A X Velocity of A) = - (mass of B X Velocity of B)

Question 19

Force (impact time)

Answer 19

Time taken (s)

Question 20

Force applied (n)

Answer 20

Spring constant (n/m) X Extension (m)

Question 21

Pressure (Pascals, Pa)

Answer 21

Area

Question 22

Pressure in a liquid

Answer 22

Height X density (kg/m3) X gravitational field strength (n/kg)