1. Resultant forces Find the resultant force on these objects. 2.3 Force and acceleration 16 December 2015 10N5N10N20N 10N 30N 10N 15N

2. 2.3 Force and acceleration 16 December 2015 5N30N 20N 5N

3. LO’s Be able to explain how force and mass affect acceleration © V Majer 2.3 Force and acceleration 16 December 2015 The F18 Hornet aircraft takes off at 140mph and weighs almost 30 tons. Aircraft carriers are not long enough for it to reach this speed. Steam catapults help the launch.

4. How are force and acceleration connected? 1.Set up apparatus as shown. 2.Attach a 50g mass to the end of the string. 3.Time how long it takes for the trolley to travel 1 metre. 4.Add another 50g and repeat. 5.Take 5 different readings. Trolley String pulley Weight Ramp Diagram Method Weight (N) Time (s) Results

5. Acceleration is proportional to force The mass pulls the trolley along the track, and it accelerates because of _______. If we increase the weight (a force), acceleration will ______. Force Acceleration Complete this sketch graph.

6. Acceleration is proportional to force The mass pulls the trolley along the track, and it accelerates because of gravity. If we increase the weight (a force), acceleration will increase. Acceleration Force Force increases so the acceleration increases.

7. Acceleration is inversely proportional to mass. If this time we change the mass of the object being pulled, increasing it by 1kg. The following graph is obtained. acceleration mass

8. You should be able to: All Be able to explain that if force is increased acceleration is increased and if Mass is increased then acceleration is decreased. Most Be able to use equation ( if given) Force = mass x acceleration. Check

9. Practical. A trolley rolls along a track. A ticker timer is used to calculate speed and acceleration Different forces are use to start it moving Then different masses are added and the experiment is repeated

10. Results 1N2N3N 1st reading (taken at 0s) 0m 2nd reading (taken at 1s) 1m2m3m Change in speed (m/s) Acceleration (m/s²) Copy and complete

11. Question What is the relationship between the acceleration and the force?(use an ER...ER relationship)

12. Results 1kg2kg3kg 1st reading (taken at 0s)0m 2nd reading (taken at 1s) 1m0.5m0.33m Change in speed (m/s) Acceleration (m/s²) Copy and complete

13. Question What is the relationship between the acceleration and the mass? ( Use an ER............ER relationship)

14. We have discovered: 1.As force increases so does acceleration. (This is common sense, the harder you push something, the faster it moves!) 2.As weight increases, acceleration decreases. (Again, this isn’t rocket science! If something’s heavy it’s hard to shift!) Copy

15. Mathematical relationships Force = Mass X Acceleration newtons kilograms metres/second² F M X A Copy