Forces

Question 1

Ways that forces affect an object

Answer 1

• change its shape
• change its size
• change its velocity
• change its direction of motion.

Question 2

Forces unit

Answer 2

Newton (N)

Question 3

Are forces vectors or scalars

Answer 3

Vector

Question 4

Unbalanced forces = ?

Answer 4

Resultant force and change in speed

Question 5

Balanced forces = ?

Answer 5

No reesultant force, so object is stationary or moving at a constant speed

Question 6

equation for:

Forces

Answer 6

F = ma

Force = mass * acceleration

Question 7

For an object moving in a circular path

More forces is needed if

Answer 7

When these increase:
* mass
* speed
* radius

Question 8

Equation for: (and unit)

Spring constant

Answer 8

k = F/x N/cm

Spring constant = Force / extension

Question 9

Define:

Spring constant

Answer 9

The force needed to stretch a spring or wire by one unit of length. Measured in N/m.

Question 10

If a spring requires a larger force to stretch then …

Answer 10

It has a higher spring constant

Question 11

Define:

Limit of proportionality

Answer 11

The highest force that can be applied before the extension of a spring or wire is no longer proportional to the force applied. Deformation occurs above this point.

Hookes law doesnt apply after this point

Question 12

Define:

Moment

Answer 12

A turning force

Question 13

Equation for: (Add unit)

moment

Answer 13

moment = force * perpindicular distance to the pivot
Nm

Question 14

What is:

The principle of moments

Answer 14

A system will not rotate (it will balance) if the clockwise and anti-clockwise moments are equal.
total clockwise moment = total anticlockwise moment

Question 15

In order to hold a light wheelbarrow at a steady height, a vertical force of 200 N is required on the handle. The length of the wheelbarrow is 1.6 m. The horizontal distance from the handle to the wheel is 1.2 m, and the horizontal distance from the wheel to the load is 0.7 m. Calculate the mass of the load.

Answer 15

340 N so 34.7kg

Question 17

Define:

Centre of gravity

Answer 17

The imaginery point within an object that the mass and weight of the object is evenly dispersed around (also known as the centre of mass).

Average position of all the mass in that object

Question 18

If the centre of gravity is low, then the object is ___

more /less stable

Answer 18

More

and vice versa

Question 19

in terms of centre of gravity

Factors that lead to more stability

Answer 19

Bigger base
Lower centre of gravity

Question 20

if forces are unbalanced _______

Answer 20

the object accelerates

Question 21

Define:

friction

Answer 21

the force between two surfaces that oppose the motion and produces heating.

Question 22

Define:

Air resistance

Answer 22

the frictional force acting on an object moving or falling through the air.

Question 23

Define:

Drag

Answer 23

the frictional force acting on an object moving through a liquid.

Question 24

in a length-force applied graph (springs)

What does thet gradient represent

Answer 24

The spring constant and it should be directly proportional

Question 25

When will a beam be balanced

Answer 25

If clock and anti clockwise forces are equal

Question 26

Equation:

Force

spring constant in the equation

Answer 26

F = kx

Question 27

If an object is moving in a circle

Answer 27

There is a force acting perpinduclar to direction of movement and towards the center of the circle.