P8(Forces In Balance)

Question 1

What is displacement

Answer 1

a measure of how far something is from its starting position, along with its direction

Question 2

What is a vector

Answer 2

A physical quantity which has magnitude and direction

Question 3

What is a scalar

Answer 3

A quantity that has magnitude but no direction

Question 4

How can a vector quantity be represented

Answer 4

By an arrow in the direction of the vector and of length in proportion to the magnitude of the vector

Question 5

What is newton’s 3rd law

Answer 5

When 2 objects interact they always exert equal and opposite forces on each other

Question 6

Forces can …

Answer 6

-Change the shape of an object
-Change an objects motion
-Change the objects state of rest

Question 7

What is a contact force

Answer 7

A force that acts on objects only when the objects touch each other

Question 8

What is newtons 1st law of motion

Answer 8

If the forces acting on an object are balanced, the resultant force on the object is zero

Question 9

What is the resultant force

Answer 9

A single force that has the same effect as all the forces acting on an object

Question 10

If the resultant force on an object is:

Answer 10

-Zero, the object stays at rest or at the same speed and direction
-greater than zero, the speed or direction of the object will change

Question 11

If an object is acted on by 2 unequal forces acting in opposite directions the resultant force is:

Answer 11

-equal to the difference between the 2 forces
-in the direction of the larger force

Question 12

If 2 forces act on an object along the same line the resultant force is:

Answer 12

-their sum, if the forces act in the same direction
-their difference, if the forces act in opposite directions

Question 13

What is a moment

Answer 13

A measure of the turning effect of the force on an object

Question 14

The moment(turning effect of the force) can be increased by:

Answer 14

-increasing the size of the force
-using a spanner with a longer handle

Question 15

Levers can be used to …

Answer 15

Exert a force that is greater than the effort

Question 16

What is the formula for moments

Answer 16

Question 17

Low gears gives …

Answer 17

Low speed and a high turning effect

Question 18

High gear gives …

Answer 18

High speed and a low turning effect

Question 19

Gears are used to …

Answer 19

Change the moment of a turning effect

Question 20

What is centre of mass

Answer 20

The centre of mass of an object is the point at which its mass can be thought of as being concentrated

Question 21

When an object is freely suspended…

Answer 21

It comes to rest with its centre of mass directly underneath the point of suspension

Question 22

What is the principal of moments

Answer 22

the sum of all the clockwise moments about any point = the sum of all the anticlockwise moments about that point

Question 23

All the forces acting on an object that don’t pas through a fixed point…

Answer 23

Can turn an object about that point

Question 24

The direction of the force and position of the fixed point …

Answer 24

Determines whether the moment acts clockwise or anticlockwise

Question 25

What’s the formula to calculate the force needed to stop an object turning

Answer 25

Question 26

The parallelogram of forces is used …

Answer 26

-to find the resultant of two forces that do act along the same line
-the resultant is the diagonal of the parallelogram that starts at the origin of two forces

Question 27

Resolving a force means

Answer 27

Finding perpendicular components that have a resultant force that is equal to the force

Question 28

For an object in equilibrium …

Answer 28

The resultant force is zero

Question 29

An object at rest is in equilibrium because…

Answer 29

The resultant force on it is zero

Question 30

Answer 30