Forces

Question 1

What is a scalar?

Answer 1

A scalar is any quantity in physics to do with magnitude and is a normal integer

Question 2

What is a vector?

Answer 2

This is any quantity in physics that has a magnitude and direction. Usually drawn with an arrow above the symbol to show the direction and magnitude

Question 3

Examples of Scalars

Answer 3

Density
Displacement
Potential difference
Power
Temperature
Wavelength
Frequency

Question 4

Examples or Vectors

Answer 4

Magnetic field
Pressure
Velocity
Acceleration
Force
Current
Momentum

Question 5

What is a force?

Answer 5

• a force can change the shape of an object and state of rest of its motion
• measured in Newtons
• when the forces are balanced the result force is balanced (equal)

Question 6

What happens when a stationary object moves?

Answer 6

• this is because of the resultant force

- it will have a certain direction depending on the speed of the object (speeds up and down)

Question 7

3 Newton mechanical forces law

Answer 7

1)
- No force acting on object it will stay at rest
- Object moving at steady speed in a straight line, continue the same
2) A force applied to an object will change it’s speed in the same direction. Called acceleration depending on Newtons applies
3) For each force applied, the same amount of force will act in s different direction

Question 8

Moment

Answer 8

• weight of the object (load)
• opposite weight is called the (effort)
• line force acts along (line of action)
• using a effort the effort needed to lift the same object is only a small fraction of it’s weight

Question 9

2 Moment formulas

Answer 9

Moments= force x distance

F1 x D1= F2 x D2

Question 10

What are gears?

Answer 10

• like levers as they multiply the effect of the engines forces
• bigger turning gap on a lower gear
• turning effect of the wheel shaft is bigger than the turning effect of it’s engine shaft

Question 11

Low gear

Answer 11

• a small gear wheel driven by the engine shaft is used to turn a larger gear wheel on the output shaft
• output shaft turns slower than the input shaft
• low gear guides low speed and high turning effect

Question 12

High gear

Answer 12

• an output shaft turns faster than the engine shaft
• turning effect of the output shaft is less than the turning effect of the engine shaft
• high gear gives high speeds and low turning effect

Question 13

Gear Formula

Answer 13

Moment= force x gear wheel radius

Question 14

Centre of mass

Answer 14

• in different objects there is a point within it that is considered the centre
• the mass of the object may be considered to act at a single point

Question 15

Description of terminal velocity graph for parachutist

Answer 15

• as he jumps speed increases, with no air resistance
• accelerates towards earth with air resistance
• reaches a terminal velocity (constant speed)
• as opens parachute a lot of air resistance (decelerating)
• continues to decelerate
• reaches terminal velocity

Question 16

What is momentum

Answer 16

• objects tendency to move in the same direction

- difficult to change direction of an object with high momentum

Question 17

Two formulas for momentum

Answer 17

• Mass (kg) x Velocity (m/s)

- m1v1=m1v1