# Who wins the battle?.

## Presentation on theme: "Who wins the battle?."— Presentation transcript:

Who wins the battle?

& & Momentum - 3m/s A 5kg medicine ball is thrown at 3m/s?
What is the momentum of the ball? If the medicine ball moves twice at fast, what is its momentum in terms of ‘p’? What mass would the ball need to have in order to have the same momentum in part a? p (kgm/s) v (m/s)

Two sumo wrestlers with masses of 160kg and 120kg respectively, collide and come to a standstill. If the 160kg wrestler rushed to the right at 3m/s, what velocity must the 120kg wrestler had?

Who exerts the greater force?

Impulse - Medicine Ball cont…
Your friend catches the 5kg medicine ball that was traveling at 3m/s. The time is takes for your friend to bring the ball to rest is .1s What is the change in momentum of the ball? What is the impulse imparted on the ball? What force does your friend have to exert on the ball in order stop it in .1s? How does this compare to the force that the ball exerts on your friend? What is the impulse imparted onto your friend? How would this affect his motion? What would the force on your friend be if it took .5s to bring the ball to rest? F(N) t(s)

Crumple Zones

Working with Impulse and Momentum:
Greatest ∆v? Greatest acceleration? Greatest ∆p? Greatest Impulse? Greatest Force? Example: Bullet and a Block of Wood A bullet with a momentum of 6.6kgm/s is fired at 300m/s into a 1kg stationary block of wood. What is the mass of the bullet? If .002s goes by from the moment of impact until the bullet is brought to rest, what is the force the wood exerted on the bullet? What was the deceleration of the bullet? How far into the wood did the bullet make it?

3 Situations Conservation of Momentum -
Explosions Inelastic Collision Elastic Collision

3 Situations Conservation of Momentum -
Explosions Inelastic Collision Elastic Collision

EXPLOSION: A 20kg cannon initially at rest shoots a 5kg ball giving the ball a velocity of +40m/s…
What will be the recoil velocity of the cannon? b) What is the impulse imparted on the ball? If the ball took .15s to leave the barrel, how much force was exerted on the ball during this time? d) What will be the acceleration of the cannon? e) If the coefficient of friction between the wheels and the ground is .8, how far back will the cannon move?

INELASTIC COLLISION: Grandma skates towards grandpa colliding with him and picking him up…
What will be the velocity of the system after the collision? What would be the velocity of the system if grandpa had a mass of 80kg? What will be v’ in terms of v1? A 8kg fish moving at 4m/s eats a smaller initially at rest. If the velocity of the big fish is 3m/s after it meal, what was the mass of the smaller fish?

ELASTIC COLLISION: Two balls collide as shown…
Total momentum before collision? Total momentum after collision? Velocity of 5kg ball after collision? What is Impulse on each ball? Graphical Interpretations… A pool ball moving at 2m/s strikes another pool ball of identical mass initially at rest. If the first pool ball is brought to rest upon collision, what is the velocity of the second ball after the collision? 5 4 3 2 1 Q) What is the impulse on a 10kg object during the first 3 seconds? V(m/s) Q) First 5 seconds? t(s) Q) How far did the object travel during the first 5 seconds?

A .3kg pool ball moving 2m/s strikes another motionless pool ball of the same mass. After the collision, the first pool bounces back at 1m/s, what is the velocity of the second ball? A .1kg bullet moving at 200m/s strikes a1kg block of wood initially at rest on a frictionless surface. What is velocity of bullet/block system after the collision? If a .2kg tennis ball feels a force of 200N for .2s while moving through the barrel, what is the muzzle velocity of the cannon?