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The Big Mo and its transfer

The Big Mo and its transfer. Momentum is a physics term; it refers to the quantity of motion that an object has. A sports team which is "on the move" has the momentum. If an object is in motion (on the move) then it has momentum. nfl football momentum.

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The Big Mo and its transfer

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  1. The Big Mo and its transfer

  2. Momentum is a physics term; it refers to the quantity of motion that an object has. A sports team which is "on the move" has the momentum. If an object is in motion (on the move) then it has momentum. nfl football momentum

  3. Let’s look at some examples of what momentum is Which will have a greater momentum, me throwing a baseball at you or Dallas Keuchel throwing it at you? Why ? More force is needed to stop a baseball thrown at 95 mph than to stop a baseball thrown at 45 mph, even though they both have the same mass

  4. Which has more momentum, a car at 45 mph or a train at 45 mph? Why ? More force is needed to stop a train than a car traveling at the same speed.

  5. So what factors are important for determining the momentum of an object? Both mass and velocity are important factors when considering the force needed to change the motion of an object. This relationship was originally developed by Newton in his 2nd Law

  6. the product of mass and velocity of an object momentum = mass x velocity ρ = mv

  7. So you got the Mo? 1. Determine the momentum of a ... • 60-kg halfback moving eastward at 9 m/s. • 1000-kg car moving northward at 20 m/s. • 40-kg freshman moving southward at 2 m/s.

  8. 2. A car possesses 20 000 units of momentum. What would be the car's new momentum if ... • its velocity were doubled. • its velocity were tripled. • its mass were doubled (by adding more passengers and a greater load) • both its velocity were doubled and its mass were doubled.

  9. An object’s momentum will change if its mass and/or velocity changes. Most common… a change in velocity. What is a change in velocity called? Acceleration a = Vf-Vo t According to Newton’s laws, a net force causes an object to accelerate, or change its velocity.

  10. Newton’s Second Law m V t m Vf-Vo t = F = ma = m v F t = p =

  11. Impulse = change in momentum FΔt = mVf-Vo So what does this mean?

  12. A 1000 kg car moving at 30 m/s (p = 30,000 kg m/s) can be stopped by 30,000 N of force acting for 1.0 s (a crash!) or by 3000 N of force actingfor 10.0 s (normal stop)

  13. Rhonda, who has a mass of 60.0 kg, is riding at 25.0 m/s in her sports car when she must suddenly slam on the brakes to avoid hitting a dog crossing the road. She strikes the air bag, which brings her body to a stop in 0.400 s. What average force does the seat belt exert on her? If Rhonda had not been wearing her seat belt and not had an air bag, then the windshield would have stopped her head in 0.001 s. What average force would the windshield have exerted on her?

  14. A 0.50-kg cart (#1) is pulled with a 1.0-N force for 1 sec; another 0.50 kg cart (#2) is pulled with a 2.0 N-force for 0.50 seconds. • Which cart (#1 or #2) has the greatest acceleration? Explain. B. Which cart (#1 or #2) has the greatest impulse? Explain. C. Which cart (#1 or #2) has the greatest change in momentum? Explain.

  15. Contact time is reduced if arm's deceleration is kept as small as possible. This is done by using "follow-through", which means to continue to push during the contact period. Some applications of impulse

  16. Spreading impulse out over a longer time means that the force will be less; either way, the change in momentum of the boxing glove, fist, and arm will be the same.

  17. Observe that the greater the time over which the collision occurs, the smaller the force acting upon the object. Thus, to minimize the effect of the force on an object involved in a collision, the time must be increased; and to maximize the effect of the force on an object involved in a collision, the time must be decreased.

  18. Conservation of Momentum

  19. CONSERVATION OF LINEAR MOMENTUM According to the law of conservation of linear momentum, the total momentum in a system remains the same if no external forces act on the system.

  20. ELASTIC AND INELASTIC COLLISIONS Elastic Collision: A collision in which objects collide and bounce apart with no energy loss. Inelastic Collision: A collision in which objects collide and some mechanical energy is transformed into heat energy.

  21. The animation below portrays the inelastic collision between a 1000-kg car and a 3000-kg truck. The before- and after-collision velocities and momentum are shown in the data tables.

  22. The animation below portrays the elastic collision between a 3000-kg truck and a 1000-kg car. The before- and after-collision velocities and momentum are shown in the data tables.

  23. Before the collision, the momentum of the truck is 60 000 Ns and the momentum of the car is 0 Ns; the total system momentum is 60 000 Ns. After the collision, the momentum of the truck is 30 000 Ns and the momentum of the car is 30 000 Ns; the total system momentum is 60 000 Ns.

  24. The animation below portrays the inelastic collision between a very massive diesel and a less massive flatcar. The diesel has four times the mass of the freight car. After the collision, both the diesel and the flatcar move together with the same velocity.

  25. A 0.105-kg hockey puck moving at 48 m/s is caught by a 75-kg goalie at rest. With what velocity does the goalie slide on the ice after catching the puck? M1 = 0.105 kg M2 = 75 kg V1 = 48 m/s V2 = 0 m/s p before= p after m1V1 + m2V2 = (m1 +m2) Vf (0.105 kg)(48m/s) + (75kg)(0) = (0.105kg + 75Kg) Vf Vf = 0.067 m/s

  26. A 0.50-kg ball traveling at 6.0 m/s collides head-on with a 1.00-kg ball moving in the opposite direction at a velocity of -12.0 m/s. The 0.50-kg ball moves away at -14 m/s after the collision. Find the velocity of the second ball. M1 = 0.50 kg M2 = 1.00 kg V1 = 6.0 m/s V2 = -12.0 m/s Vf1 = -14 m/s p before = p after m1V1 + m2V2 = m1Vf1 + m2V2f (.5kg)(6m/s) + (1kg)(-12m/s) = (.5kg)(-14m/s) + (1kg)(V2f) V2f = - 2 m/s

  27. A 3000-kg truck moving rightward with a speed of 5 m/s collides head-on with a 1000-kg car moving leftward with a speed of 10 m/s. The two vehicles stick together and move with the same velocity after the collision. Determine the post-collision velocity of the car and truck. M1 = 3000 kg M2 = 1000 kg V1 = 5.0 m/s V2 = -10 m/s p before = p after m1V1 + m2V2 = (m1+ m2 )Vf (3000kg)(5m/s) + (1000kg)(-10m/s) = (3000kg + 1000kg) Vf Vf = 1.25 m/s, right

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