Available Answers

1. 1.

   Complete each sentence with the correct option.

   1. We should eat food because it gives our body ________________.
      1. blood
      2. energy
      3. force
      4. work
   2. Sugar and potato are ________________ foods.
      1. sweet
      2. body-building
      3. protective 
      4. energy-giving
   3. Microwave ovens use ________________ energy to cook food.
      1. electrical
      2. solar
      3. water
      4. wind
   4. A solar cooker gets energy from the ________________.
      1. moon
      2. sun
      3. stars
      4. earth
2. 2.

   Why do we need energy?​​​​​

3. 3.

   Describe the scientific meaning of work.

4. 4.

   Give three examples of work done.

5. 5.

   Determine if work is done in the following cases. Write 'Work is done' or 'Work is not done' to complete each sentence.

   1. _______________ when we use force to push a toy car and it moves.
   2. _______________ when a person is standing in one place with a heavy load on his head.
   3. _______________ when we play a game of chess.
   4. _______________ when we carry books from the library to the classroom.
   5. _______________ when vegetables are kept inside the fridge from the kitchen.
6. 6.

   How is the energy that we get from food obtained indirectly from the sun?