6.1.1 Energy changes in a system, and the ways energy is stored before and after such changes

Question 1

what is a system?

Answer 1

A system is an object or group of objects.

Question 2

what happens when a system
changes?

Answer 2

There are changes in the way energy is stored

Question 3

Energy and work done are measured in

Answer 3

joules

Question 4

1 kJ (1 kilojoule)

Answer 4

1000 J

Question 5

1 MJ (1 megajoule)

Answer 5

1,000,000 J

Question 6

The total amount of energy in a closed system is

Answer 6

constant

Question 7

change in energy store for an object projected upwards

Answer 7

the kinetic energy store of the ball decreases and the gravitational potential energy store of the ball increases

Question 8

a moving object hitting an obstacle

Answer 8

the kinetic energy in a moving object, once it hits an obstacle, the kinetic energy can be transferred into many different types of energy. It can be transferred to the surroundings as thermal energy and sound waves.

Question 9

an object accelerated by a constant force

Answer 9

energy is required to accelerate the object; this could be chemical, thermal or electrical (the situation will determine the specific type of energy). This energy will then be converted into kinetic energy (used to accelerate the object).

Question 10

a vehicle slowing down

Answer 10

To slow down the vehicle, the kinetic energy of the movement will be transferred into another store of energy. This energy could be sound waves and thermal energy.

Question 11

bringing water to a boil in an electric kettle

Answer 11

When we are heating up water in an electric kettle, we are transferring electrical energy into thermal energy, which is used to heat up the water

Question 12

a system can be changed by?

Answer 12

heating
* work done by forces
* work done when a current flows

Question 13

mass is always measured in

Answer 13

kg

Question 14

speed is measured in

Answer 14

metres/second (m/s)

Question 15

spring constant is measured in

Answer 15

newtons per metre (N/m)

Question 16

what is specific heat capacity?

Answer 16

The specific heat capacity of a substance is the amount of energy
required to raise the temperature of one kilogram of the substance
by one degree Celsius.

Question 17

what is power?

Answer 17

Power is defined as the rate at which energy is transferred or the
rate at which work is done

Question 18

what is time always measured in?

Answer 18

seconds

Question 19

An energy transfer of 1 joule per second is equal to?

Answer 19

a power of 1
watt.