Momentum problems?

A hockey puck has a mass of 0.127 kg and is at rest. A hockey player makes a shot, exerting a constant force of 32.0 N on the puck for 0.16 s. With what speed does it head toward the goal?



A 94 kg fullback, running at 8.2 m/s, collides in midair with a 134 kg defensive tackle moving in the opposite direction. Both players end up with zero speed.

(b) What was the fullback's momentum before the collision?

(c) What was the change in the fullback's momentum?

(d) What was the change in the tackle's momentum?

(e) What was the tackle's original momentum?

(f) How fast was the tackle moving originally?



A 0.105 kg hockey puck, moving at 35.0 m/s, strikes a 0.240 kg octopus thrown onto the ice by a hockey fan. The puck and octopus slide off together. Find their velocity.



A football punter accelerates a 0.40 kg football from rest to a speed of 19.0 m/s in 0.10 s. What constant force does the punter exert on the ball?Momentum problems?
I don't usually answer homework questions, but you're being led astray by kingkongchess, and you'll pay the price at test time anyways if you don't figure these out for yourself, so I'll answer one and give you some hints on where to look for with the others.



1) F=ma=dp/dt=m x dv/dt = constant, so m x delta v=const. x delta t. More simply, m x v=const. x time, but be warned, this WONT work unless the force is constant! Anyways, v=(32N x .16s)/.127kg = 40.3 m/s (just divide away the mass for the velocity). A little more likely than 1575 m/s (~3500 mph!), no? That'd be some hockey player!



2) kingkongchess sets it up exactly right; all answers come from the conservation on momentum, m1v1=m2v2. This is also true for problem 3.



3) Trickier. Before collision, the system consists of 2 seperate momentums, p1 and p2. After the collision, the system consists of the single body (with momentum (m1 + m2) x v3 ) stuck together. Conservation of momentum states that the momentum of the system before the collision must equal the momentum of the system after collision. Just make them equal, and solve for what you're looking for.



4) The word 'accelerates' should give you a clue. Think 'force' when you hear the word accelerates, and when you think force, think 'rate of change in momentum'. Put these ideas together, you'll have your answer.Momentum problems?
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I never liked math or science...Momentum problems?
I dont have a clueMomentum problems?
first question..



Force/Time = work = mass*velocity

32/0.16 = 0.127 V

V = 1574.8 m/s



Second Question



conservation of momentum



M1*V1 = M2*V2

94*8.2 = 134*V

V = 5.752



c. change in momentum = negative orig. momentum = -770.8



d. change in momentum = negative orig. momentum = -770.8



orig. momentum= 770.8



... wait... i might be wrong..

nex question..



M1*V1 + M2*V2 = (M1+M2)V



0.105*35 + 0.24*0 = (0.105+0.24)V

V = 10.652



final question..

kinematics.. you know initial vel., final vel., and time

..

V = Vi+AT

19 = 0 + A(10)

A=1.9



F = MA = 0.4*1.9 = 0.76



...

i think these are right..

.. if i'm worng, it must be my fluke on the calc..

but the theorems are correct..



godspeed