UNIT_4 MACHINES

ACTIVITIES:

1.- Name there machines with one or few parts, and three machines with many parts.

Lever, knife, scissorss, nutcracker, car, bus, computer, train.

2.- Calculate the work requiered to lift a weight of 1200N to a height to 9m. 

1200N : 90m = 13,3333

3.- A person pushes a suitcase across a railway station of 20m. It the total performed is 1200J, How much force had to be applied?

1200:20= 60 N

4.- Find out how many simple machines are combined in a wheelbarrow.

Wheel, lever, axis

5. Complete the sentences:

·                     a) Machines are objects that help save time and energy

·                     b) Planes and cars are compound machines.

·                     c) All machines need energy to function.

6. Complete a sentences of these objtects where you describe the ENERGY that they use for. 

·                     a) vacuum: electricity and fueza del vacio.

·                     b) helicopter: fuerza eolica.

·                     c) stapler: mecanic energy.

7. You should always take care when using machines. Think of these machines that you can use and write how the canbe dangerous and give a safety rule.

·                     a) Knives: We can cut ourself. We shouln´t play with them.

·                     b) plug: we can burn our fingers or electrized our body and die.
·                     c) jigsaw: we have solve it and develop our brains.

·                     d) glue pistol: you can burn ourself and glue instruments.

·                     e) drill: we can cut our selves.

8. What sort of  SIMPLE MACHINES are these objects?:

·                      a baseball bat : 3º type of lever

·                      the front of a ship : wedge

·                     the fan blades : wheel
·                      a toilet paper dispenser : inclinate paper

·                      a door knob : axe

·                      a broom : 3º type of lever

 9.  Find out the MACHINES that these objects got:

·                      Stapler: a) lever b) wedge

·                     Wheel barrow:  a) lever b) wheel

 10.- What category do the following levers belong to? 

a) Screwdriver used to open a can. 2º
b) Fihsing pole. 3º
c) Bicycle brake. 2º
d) Balance. 1º

11.- The weightof a boy sitting on a see-saw(balancín) 1m from the fulcrum generates a force of 440N. How much force must his little sister produce if she sits 2m from the fulcrum?
1m 
440N                     1 x 440 = 2 x y
2m                         y = 220N

12.- A force o 5000N is requiered to lift a stone. However, if a 2m lever is availeble and it is placed with the fulcrum 25cm from the stone, how much force must be applied to the lever. 
5000N
2m                                     5000 x 25 = 200 x y
25cm                                  y= 625N

ACTIVITIES

• a) Write in one sentence what the teacher in the video is trying to explain.

h           he tries to explain us how levers (simple machines) can help us in a daily life.

• b) What are the simplest of all machines based on?

              they are based on levers.

• c)What type of work is put in a machine? 

y            force and energy

• d) Archimedes said: “Give me a fulcrum and I will move the Earth”
• e) Which force is bigger in a lever?

              the force is bigger if it is near the fulcrum.