Energy Part 1

Define energy.​ ​ (a)  

State the SI unit of energy.​ (b)  

• Energy is the capability to do work
• Energy is the capacity to do force
• Energy is the capacity to do momentum
• joule
• newton
• pascal

Organize these options into the right categories

Groups:

(a) Kinetic energy

,

(b) Gravitational potential energy

,

(c) Elastic potential energy

,

(d) Chemical potential energy

• explosives
• batteries
• Moving or vibrating objects

• Object on a hill

• Flying airplane

• Book on a shelf

• Position or height of an object

• Water at the top of a waterfall

• Running car

• Stretched rubber band

• Skydiver before jumping

• Compressed spring

• food
• Inflated balloon

• Stretched (or compressed) object

• Bowstring before release

• gasoline
• fuel

• Rolling ball

• Flowing water

The Principle of Conservation of Energy ​ is considered a universal law of physics that is true for all scenarios. According to this principle, (i) energy cannot be ​ ​ (a)   or ​ (b)   ; (ii) energy can be ​ (c)   from one form to another, or transferred from one body to another; (iii) the total amount of energy available in a closed system is ​ (d)   .

• destroyed
• transformed
• constant
• made
• created
• produced

A car with 20 kJ of energy initially travels up an inclined road. Its engine supplies an additional 10 kJ for a short while. Assuming there is no loss of energy to the surroundings, explain the final amount of energy possessed by the car, using the Principle of Conservation of Energy.

sum of initial energies in the system ​ (a)   sum of final energies in the system ​ (b)  

• 20 kj + 10 kj
• 30 kj
• 20 kJ - 10 kJ, 10 kJ
• 15 kJ + 5 kJ, 20 kJ
• 25 kJ + 5 kJ, 30 kJ

Define efficiency.​ ​ Efficiency is defined as the ​ (a)   of ​ (b)   that is converted into useful ​ (c)  

• percentage
• input energy
• output energy
• waste
• total
• energy loss
• useless energy

The diagram shows an LED light bulb.

a. input per second ​ (a)   ​

b. wasted energy per second​ (b)  

c. efficiency of LED light bulb​ (c)  

• 8.0 W
• 0.5 W
• 94 %
• 10.0 W
• 1.0 W
• 80 %