Forces and their interactions

What is a force

A push or pull factor that acts on an object due to the interaction with another object

Define contact force

Objects are physically touching

Define non contact forces

The objects are physically separated

Examples of non contact

• Gravitational

• Magnetic

• Electrostatic

Examples of contact

• Friction

• Air resistance

• Tension

is force a scalar or vector quantity

Vector

Define scalar

Only have a magnitude

Define vector

have magnitude and an associated direction

Examples of scalar quantities

• Mass

• Volume

• Temperature

• Speed

• Energy

Examples of vector quantities

• Weight

• Velocity

• Displacement

• Acceleration

• Momentum

Define weight

the force acting on an object due to gravity.

Why is the force of gravity close to the Earth

It is due to the gravitational field around the Earth.

The weight of an object depends on…

the gravitational field strength at the point where the object is.

The weight of an object can be calculated using the equation

weight  = mass × gravitational field strength

Weight is measured using a…

calibrated spring-balance (a newtonmeter).

The weight of an object and the mass of an object are…

directly proportional

What is the unit for

1) weight

2) gravitational field

1) newtons

2)N/kg

What is meant by an objects centre of mass

The single point where an objects weight can be considered to act through

What is the name given to the single force that is equivalent to all other forces acting on a given object

The resultant force