1. 2.2 Resultant force 6 + 5 = 15 – 10 = 3a + 5a = Try these sums
26 April 2017
6 + 5 =
15 – 10 =
3a + 5a =
100N – 50N =
40 – 40 =
100N – 200N =
50kN – 25kN =
1kN – 500N =
Try these sums

2. 2.2 Resultant force 6 + 5 = 11 15 – 10 = 5 3a + 5a = 8a
26 April 2017
6 + 5 = 11
15 – 10 = 5
3a + 5a = 8a
100N – 50N = 50N
40 – 40 = 0
100N – 200N = -100N
50kN – 25kN = 25kN
1kN – 500N = 500N (1k = 1000)

3. 2.2 Resultant force What is a resultant force?
26 April 2017
What is a resultant force?
What happens if the resultant force is zero?
What happens if there is a resultant force?
Voyager 2 was launched in Since then it has had no main rocket engine to power it. The spacecraft is now at the edge of the Solar System travelling at mph!
How can it keep going?

4. Resultant force
A single force used to represent all the forces on an object.
Resultant =
10N
10N
20N
What is the missing resultant force?
10N = ?
20N

5. Newton’s 1st Law of motion
When the resultant force on an object is zero:
An object stays still
Has a constant velocity
Explain how a skater carries on moving with no effort on ice. Which force is zero on ice?

6. When the resultant force is not zero the object changes its velocity.
What happens when the:
Weight is more than the Lift force?
Lift is more than the Weight?
Weight equals the Lift?

7. Accidents Draw a diagram to show the lorry hitting the car. Include:
The direction the lorry was travelling
The force needed to stop the lorry
The force on the car.

8. Investigation Use a trolley to look at Newton’s 1st Law.
When the resultant force on an object is zero:
An object stays still
Has a constant velocity
Use a trolley to look at Newton’s 1st Law.
How can you get the trolley to move at a constant speed?
Which forces must be balanced for this to happen?
books
Trolley

9. Key Points Start Resultant Force Effect on object 1 At rest Zero
Copy this table
Start
Resultant Force
Effect on object 1
At rest
Zero
Stays at rest 2
Moving
Velocity stays the same 3
In direction of movement.
Accelerates 4
Against direction of movement
Decelerates