Ch 150407052236-conversion-gate01

How are forces and motion related? Chapter

11: Lesson 1:

Motion

Change in position

Types of motion

1) Up and down

motion

2) Straight line motion

3) Round

and round motion

4) Zigzag motio

n

5) Back and

forth motion

1) Up and down motion

2) Straight line motion

3) Round and round motion

4) Zigzag motion

5) Back and forth motion

Motion can be:

Fastand

Slow

motion

motion

Same direction

Or

Change direction

Draw arrows on the following pictures showing the type of motion.

Activity

DistanceHow far it is

from one position to

another position

Measure the distance of the arrows shown using a ruler or a measuring tape.

Activity

1

43

2

5

DirectionAn object can

move north, south, east or

west.

ForcesA push or a

pull.Example:- When you open a door

(pull)- When you close a drawer

(push)- When you are kicking the

ball (push)

A force can:

1) Make something move

2) Change

the direction

of a moving object

3) Change

the speed of a moving

object

4) Change

and objects shape

Types of forces:

1) Balanc

ed forces

2) Unbalanced

forces

1) Balanced ForcesForces that cancel each

other when acting together on a single

object.Example:

Both forces

are equal so the object

does not move

Balanced forces do not change motion.

- If an object is not moving it will not move.

- If an object is moving it will continue to move in the same direction without changing speed.

2) Unbalanced

ForcesForces that are not equal

to each other .- It causes a change in motion.- The greater force determines

the direction of motion.- Unbalanced forces can make

and object start to move, speed up, slow down or change directions.

GravityThe force that

makes things fall to the ground on

earth.

Mass vs. Weight- How much

matter in an object.

- Measured by g or kg

(not a force)

- Force caused by gravity

pulling down on the mass of

an object.- Measured in Newton (N)

How can we measure weight?Weight is measure using

a force meter.

• Friction is a force between two surfaces that are sliding, or trying to slide across one another, for example when you try to push a toy car along the floor.

• Friction always works in the direction opposite from the direction the object is moving, or trying to move. It always slows a moving object down.

Moving

Friction

• Friction also produces heat. For example, if you rub your hands together quickly, they get warmer.

• The amount of friction depends on the materials from which the two surfaces are made. The rougher the surface, the more friction is produced. For example, you would have to push a book harder to get it moving on a carpet than you would on a wooden floor. This is because there is more friction between the carpet and the book than there is between the wood and the book.

• Friction can be a useful force because it prevents our shoes slipping on the pavement when we walk and stops car tyres skidding on the road.

• Ice causes very little friction, which is why it is easy to slip over on an icy day. But this is a good thing for ice skating and sledging.

• Sometimes we want to reduce friction. For example, moving parts inside a car engine are lubricated with oil, to reduce friction between them. The oil holds the surfaces apart, and can flow between them. The reduced friction means there is less wear on the metal, and less heat produced.

• Air resistance is a type of friction between air and another material. When an aeroplane flies through the air, for example, air particles hit the aeroplane, making it more difficult for the aeroplane to move through the air.

• Some shapes, known as streamlined shapes, cause less air resistance than others. Aeroplanes and cars are streamlined, so that they move through the air as easily as possible.