P8- Forces In Balance

Question 1

What is displacement?

Answer 1

A distance in a given direction without change of direction.

Question 2

What is a vector?

Answer 2

Physical quantities that have direction and magnitude

Question 3

Example of vectors?

Answer 3

Acceleration, force , momentum, weight and gravitational field strength.

Question 4

What is a scalar?

Answer 4

Physical quantities that have size but no specific direction.

Question 5

Example of scalar?

Answer 5

Speed, distance, time, mass, energy and power.

Question 6

What is a magnitude?

Answer 6

The size of a quantity. Eg 5km.

Question 7

What does the arrow on a vector represent?

Answer 7

The direction of the vector

The magnitude of the vector quantity.

Question 8

What is Newtons third law of motion?

Answer 8

When two objects interact with each other, they exert equal and opposite forces on each other.

Question 9

What is a contact force?

Answer 9

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

Question 10

What is the driving force on a car and what does it do?

Answer 10

It is the force that makes it move and pushes the car forward due to the friction between the ground and the tyre of each drive wheel.

Question 11

What ks newtons first law of motion?

Answer 11

It states that if the forces acting in an object are balanced, the resultant force on the object is zero.

So if the object is at rest, it stays stationary and if the object is moving, it keeps moving with the same speed and in the same direction.

Question 12

What happens if the resultant force on an object is mot zero?

Answer 12

The object is not balanced.

So the object is equal to the difference between the two forces and goes in the direction of the larger object.

Question 13

How do you work out the resultant force?

Answer 13

Take away the smaller force from the bigger force.

Question 14

What is the moment?

Answer 14

The turning effect of the force and can be increased by the size of the force and using an object with a longer handle.

Question 15

What is the weight of an object called?

Answer 15

A load

Question 16

What is the force the person applies called?

Answer 16

The effort

Question 17

What is the line of action?

Answer 17

The line that a force acts along

Question 18

How can levers be used?

Answer 18

To exert a force that is greater than the effort.

Question 19

How do you work out moment?

Answer 19

Moment=force X perpendicular distance from the line of action of the force to the pivot.

Question 20

What are gears used for?

Answer 20

To change the moment of a turning effect

Question 21

How do you increase the moment of a turning effect?

Answer 21

A small gear wheel needs to drive a larger gear wheel.

Question 22

How do you get a low turning effect?

Answer 22

A large gear wheel needs to drive a small gear wheel

Question 23

What is the centre of mass?

Answer 23

Is the point at which its mass can be thought of as being concentrated.

Question 24

What happens when the object is suspended ?

Answer 24

It comes to rest with the centre of mass directly below the point of suspension.

Question 25

Where is the centre of mass in a symmetrical object?

Answer 25

Where all the lines of symmetry meet is where the centre of mass is.

Question 26

What is the principle of moment?

Answer 26

The sum of the clockwise moment of any point = the sum of the anticlockwise moment of this point.

W1D1 = W2D2

Question 27

What is the parallelogram of forces?

Answer 27

A scale diagram of two force vectors. It is used to find out the resultant of two forces that do not act along the same line.

Question 28

What does resolving a force mean?

Answer 28

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