Forces And Motion

Question 1

What is a vector quantity

Answer 1

A quantity that has a magnitude and a direction

E.g. force,velocity, displacement, acceleration,momentum etc

Question 2

What is a scalar quantity?

Answer 2

A quantity that has only a magnitude but no direction
E.g. speed,distance,mass,temperature,time, etc

Question 3

What is displacement?

Answer 3

The shortest distance between two points

Question 4

Newtons 3rd law

Answer 4

For every force there is an equal and opposite reaction force

Question 5

What is a moment

Answer 5

The turning effect of a force

Question 6

Moment equation

Answer 6

M=FD

M=moment (Nm)
F= force(N)
D=Distance(m)

Question 7

What is the line of action

Answer 7

The line along which a force acts

Question 8

What is the origin of a moment called

Answer 8

A pivot

Question 9

To increase a moment

Answer 9

•Increase force applied
•Increase distance the force is applied from the pivot

Question 10

How many moments can be acting on an object

Answer 10

1 or more

Question 11

How are moments described?

Answer 11

Due to moments being a turning force9effect) we refer to them as clockwise or anti-clockwise

Question 12

What is the principle of moments

Answer 12

At equilibrium the sum of clockwise and anticlockwise moments are equal

Question 13

What are levers

Answer 13

Levers are usually force multipliers which transmit turning effects of a force, we apply an input force which is outputted somewhere else

Question 14

Rules of input and output forces in levers

Answer 14

If the input+ output forces are on different sides of the pivot like scissors they will act in diff directions but if on the same side as the pivot (such as a wheel barrow) the forces will act in the same direction

Question 15

Is the output forces usually greater or smaller

Answer 15

Greater

Question 16

Method for the principle of moments measuring and unknown weight

Answer 16

A
Method:
1. Place a wooden beam over the triangular
block, with the block in the centre of the
beam acting as a pivot.
2. Place or suspend the known weight on one end of the beam
3. Measure the distance from the pivot to the centre of the weight
4. Place or suspend the unknown weight on the other end of the beam and move it until the beam is perfectly balance
5. Measure the distance from the Pivot to the centre of the unknown weight
6. use this value to calculate the value of
unknown weight, using the formula
Clockwise moments=anticlockwise moments
W1d1, = W2d2

Question 17

Notes about gears

Answer 17

•Turn in opposite directions
•If the size of the second gear is double the first the turning effect doubles

Question 18

What is friction?

Answer 18

The force wen one object slides over another object, friction tries to stop the movement , it is a force that acts in opposition to a moving object

Side note- it is a nuisance ad it often converts kinetic energy into thermal energy

Question 19

What is centre of mass?

Answer 19

The centre of mass of an object is the point at which an objects mass seems to be most concentrated

Question 20

How to find the centre of mass of a regular object.

Answer 20

Draw lines of symmetry along the objet e.g from corner to corner and side to side , the point at which all the lines cross is the centre of mass

This is because the centre of mass lies along the axis of symmetry

Question 21

What is stability

Answer 21

The tendency o an object to not topple

Question 22

How to increase stability

Answer 22

•Increase the wideners of its base
•Ensure its centre of mass is as low as possible

Question 23

Why do objects topple?

Answer 23

If the line of action of the weight force lies outside for the object , there will be a turning force and the object will topple