P2.2 Forces

Question 1

What are forces measured in?

Answer 1

Newtons (N)

Question 2

How would you show force on a diagram? (3)

Answer 2

The direction of the arrow shows the direction of the force
The length of the arrow is proportional to the size of the force
Arrows point outwards of the diagram

Question 3

Name 5 forces

Answer 3

Upthrust (only in water)
Drag
Friction
Weight
Thrust

Question 4

What’s the resultant force?

Answer 4

The overall force acting on an object

Question 5

How do you work out the resultant force?

Answer 5

You minus the smaller force from the larger force

Question 6

How much resultant force does a stationary object have?

Answer 6

Zeroooooo

Question 7

Describe the resultant force of a moving object

Answer 7

At a constant speed it has no resultant force

Of its accelerating or decellerating then it has a resultant force

Question 8

What’s acceleration measured in?

Answer 8

m/s squared

Question 9

How’d you work out force?

Answer 9

Mass X acceleration

Question 10

What’s the terminal velocity?

Answer 10

The maximum velocity that an object is able to achieve

Question 11

What factors affect the terminal velocity?

Answer 11

The driving force that the object can generate
How streamlined the object is
The fluid the object is travelling through

Question 12

What’s the gravitational field strength on earth?

Answer 12

10 N/kg

Question 13

How do you calculate weight?

Answer 13

Mass X gravitational field strength

Question 14

What’s the relationship between the force applied and the extension of a spring?

Answer 14

Directly proportional

Question 15

What’s Hooke’s Law?

Answer 15

The extension of an object is directly proportional to the force that is applied to it provided that the limit of proportionality is not exceeded
F = k X e
F = force
k = Spring constant
e = extension

Question 16

What’s the spring constant measured in?

Answer 16

N/m

Question 17

The greater the force constant the _______ the material.

The force constant can be found by calculating the _________ ___ __ ________.

Answer 17

1. Stiffer

2. Gradient of a force

Question 18

Explain why a parachutist reaches a terminal velocity and why opening the parachute reduces the terminal velocity (6)

Answer 18

Just as the parachutist leaves the plane the only force acting in him is weight
Then the air resistance force increases and he carries in getting faster because the air resistance force is less than his weight
He reaches a terminal speed when the air resistance and weight force are balanced
Then when he opens the parachute the surface area increases and that increases the air resistance meaning the forces are unbalanced and the parachutist slows down
Finally the parachutist reaches another terminal velocity at the end of the jump when the forces balance again