Chapter 3 formulas

Question 1

The formula to find “Joule”?

Answer 1

1J = 1N * 1m

J-> Joule
N-> Newton
m-> metre

Question 2

The formula for energy efficiency?

Answer 2

Energy efficiency = amount of useful energy/amount of energy consumed * 100

Question 3

The formula for heat?

Answer 3

Q = ΔEt

Q-> Heat (in joules)
ΔEt-> Variation in thermal energy (in joules)

Question 4

specific heat capacity

Answer 4

Q = mcΔT

Q-> Heat (in joules)
m-> mass (in g)
c-> specific heat capacity (in j/g°C)
ΔT-> temperature variation (in °C)

Question 5

What does ΔT mean?

Answer 5

ΔT = Tf - Ti

Tf-> final temperature (in °C)
Ti-> temperature variation (in °C)

Question 6

The formula for kinetic energy?

Answer 6

Ek = 1/2mv²

Ek-> Kinetic energy of the object (in joules)
m-> mass of the object (in kg)
v-> velocity of the object (in m/s)

Question 7

The formula for gravitational potential energy?

Answer 7

Ep = mgh

Ep-> Gravtiational potential energy (in J)
m-> mass of the object (in kg)
g-> gravitational field intensity (in N/kg)
h-> height of the object above the reference surface (in m)

Question 8

What is Earth’s gravitational field intensity?

Answer 8

It is 9.8 N/kg

Question 9

The formula for mechanical energy?

Answer 9

Em = Ek + Ep

Em-> mechanical energy (in joules)
Ek-> kinetic energy (in joules)
Ep-> potential energy (in joules)

Question 10

The formula for average speed?

Answer 10

v = d/Δt

v-> average speed (in m/s)
d-> distance travelled (in m)
Δt-> time variation/travelling time (in s)

Question 11

The formula of force?

Answer 11

1N = 1kg * 1m/s²

Question 12

The formula for gravitational force?

Answer 12

N= 1 )( kg*m/s²

Question 13

The formula relating to weight, gravitational force & mass?

Answer 13

w = Fg = mg

w- weight (in N)
Fg - gravitational force (in N)
m - mass (in kg)
g - gravitational field intensity (in N/kg)