Science 9 Quarter 4 MELC 21 Impulse and Momentum.pptx

It contains activities about the Science 9 Quarter 4 MELC 21 Impulse and Momentum

1. MOMENTUM & IMPULSE

2. Relate impulse and momentum to collision of objects (e.g. Vehicular collision) 21 MOST ESSENTIAL LEARNING COMPETENCY Quarter 4

3. MOMENTUM What is momentum? MOMENTUM is a moving object’s tendency to resist any change in its state of motion; inertia in motion .

4. MOMENTUM For bodies moving at the same velocity, the more massive body has greater inertia in motion therefore has greater momentum.

5. MOMENTUM For moving bodies with the same mass, the faster body has greater inertia in motion therefore has greater momentum.

6. MOMENTUM The momentum (p) of a body is the product of its mass (m) and its velocity (v), as in the equation: p = mv.

7. SAMPLE PROBLEM What is the momentum of a 22-kg grocery cart which travels at 1.2 m/s? Given: 22 kg – m, 1.2 m/s – v, p - ? Formula: p = mv Solution: p = (22 kg)(1.2 m/s) Answer: p = 26.4 kg · m/s

8. SAMPLE PROBLEM What is the momentum of a child and wagon if the total mass of the child and wagon is 31 kg and the velocity is 1.5m/s? Given: 31 kg – m, 1.5 m/s – v, p - ? Formula: p = mv Solution: p = (31 kg) (1.5 m/s) Answer: p = 46.5 kg · m/s

9. SAMPLE PROBLEM A bowling ball of 35.2kg, generates 218 kg.m /s units of momentum. What is the velocity of the bowling ball? Given: 35.2 kg, 218 kg · m/s – p, v - ? Formula: p = mv v = p/m Solution: v = (218 kg · m/s) / 35.2 kg Answer: v = 6.19 m/s  

10. IMPULSE In physics, an external force acting on an object over a specific time leads to a change in momentum of the object. A special name is given to the product of the force applied and the time interval during which it acts: impulse . I = Ft

11. IMPULSE In physics, an external force acting on an object over a specific time leads to a change in momentum of the object. Impulse is the change in momentum Ft = Δ p Ft = m( vf -vi)

12. SAMPLE PROBLEM A cart is pushed with a force of 25 N in 4 seconds which caused it to move. What is the impulse imparted on the cart? Given: 25 N – F, 4 s – t Formula: I = Ft Solution: I = (25 N) (4 s) Answer: 100 Ns or 100 kg · m/s N = kg · m/s 2

13. SAMPLE PROBLEM What impulse is needed to change the speed of a 10.0 kg body from 20.0 m/s to 12.0 m/s? Given: 10kg – m, 20 m/s – vi, 12 m/s – vf , I = ? Formula: I = m( vf -vi) Solution: I = 10 kg (12-20) Answer: I = -80 kg m/s

14. SAMPLE PROBLEM An offensive player passes a football of mass 0.42 kg with a velocity of 25.0 m/s due south. If the player is in contact with the ball for 0.050 s, what is the magnitude of the average force he exerts? Given: m = 0.42 kg, vf = 25 m/s, vi = 0 m/s t = .05 s, F = ? Formula: Ft = m( Vf -Vi) F = [m( vf -vi)]/t Solution: F = [0.42 kg(25m/s – 0 m/s)]/0.05s Answer: F = 210 kg•m /s2  

15. APPLICATIONS SEATBELT When a vehicle suddenly stops, it experiences impulse, change in momentum. They are designed to keep car occupants inside the car where it's likely to be safer during a crash, and they stretch just a bit, helping to increase the time it takes for the impulse to be absorbed.

16. APPLICATIONS RIDING THE PUNCH When a boxer recognizes that he will be hit in the head by his opponent, the boxer often relaxes his neck and allows his head to move backwards upon impact. A boxer rides the punch in order to extend the time of impact resulting in the decrease of force, minimizing the effect of the force in the collision