Describe the difference between scalar and vector quantities

Scalar has magnitude only Vector has magnitude and direction

What is a resultant force?

The overall force acting on an object

What is the difference between mass and weight?

Mass has magnitude only (scalar) Weight has direction (vector) Mass is measured in kg Weight in measured in N

What factors affect the weight of an object?

Mass, m (kg) Gravitational Field Strength, g (N/kg)

Calculate the resultant force on the car

500N - 500N = 0N

Calculate the resultant force on the car

500N - 200N = 300N forwards

Calculate the resultant force on the car.

500N - 200N = 300N backwards

Describe the motion of the car.

Moving at a constant velocity.

Describe the motion of the car

Accelerates to the right.

Velocity increases in the forwards direction.

Describe the motion of the car

Velocity decreases

Car decelerates

Write an equation that links weight, mass and gravitational field strength

Weight = mass x gravitational field strength

W = m x g

What is the value of gravitational field strength, g, on Earth?

10N/kg

What is the weight of a 90kg astronaut on Earth?

W = m x g

= 90 x 10

= 900N

A space probe has a mass of 3000N on Earth. What is its mass?

W = m x g

m = W ÷ g

= 3000 ÷ 10

= 300kg

A mars rover with a mass of 185kg has a weight of 685N on Mars. Calculate the gravitational field strength on Mars.

W = m x g

g = W ÷ m

= 685 ÷ 185

= 3.70N/kg

The mass of a spanner on Earth is 0.2kg, and its weight is 2N. The spanner is taken to the Moon as part of a toolkit.

Compare the mass and weight of the spanner on the Moon.

mass of the spanner is the same on the moon.

Weight will be less on the Moon.

as the gravitational field strength is smaller on the Moon.

Describe what acceleration means.

Change in velocity in a certain time.

or

a = (v-u)÷t

What two factors affect the size of acceleration of an object?

The size of the force (bigger force = bigger acceleration)

The size of the mass (bigger mass = smaller acceleration)

What is the equation that links force, mass and acceleration?

force = mass x acceleration

F = m x a

A motorcycle has a mass of 200kg. What force is needed to give it an acceleration of 7m/s^{2}?

F = m x a

= 200 x 7

= 1400N

A car with a mass of 1500kg is accelerated with a force of 800N. Calculate the acceleration of the car.

F = m x a

a = F ÷ m

= 800 ÷ 1500

= 0.53m/s^{2}

What is inertial mass?

The force on an accelerating object divided by its acceleration

A force of 160N on a bike provides an acceleration of 2m/s^{2}. Calculate the intertial mass of the bike and its rider.

mass = F ÷ a

= 160 ÷ 2

= 80kg

What conclusion can be made from this graph?

acceleration is proportional to force