Solve Physics Q: Momentum - 0.15kg Ball Stops at 390 N

In summary: Thanks for getting me started!In summary, the baseball is slowed to a stop by the catcher who exerts a constant force of 390 N. It takes .01s for this force to stop the ball. The ball travels .507 meters before stopping.
  • #1
JMarino
12
0

Homework Statement



A 0.15 kg baseball moving at +26 m/s is slowed to a stop by a catcher who exerts a constant force of 390 N. How long does it take this force to stop the ball? How far does the ball travel before stopping?



Homework Equations





The Attempt at a Solution


For P=mV = 0.15Kg x 26M/s = 3.9Kgm/s. Then what equation?
I = F deltaT = m deltaV
deltaT=m deltaV / F = 3.9/390 = .01s Is that correct?
What about last question of travel distance. Is speed constant?
 
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  • #2
first part looks good.

The speed cannot be constant, after all its 26m/s one instant, and zero the next.

there are several approaches to second part, have you learned about work at all?
 
  • #3
somewhat, where do you suggest I look specifically?
 
  • #4
work = force x distance moved. There are two variables I do not know in this equation...
 
  • #5
well there's a nifty thing known as work-energy theorum, which would suggest that right before the ball hits the mitt, it has a total energy, and when it comes to rest it has less, and that the difference would we the dot product of force and distance, in this case just the simple product of the two, or force*distance. That distance is the one you seek.
 
  • #6
JMarino said:
work = force x distance moved. There are two variables I do not know in this equation...


see above as well. I'm not trying to be confusing, its just that the energy can be a combination of different types such as potential and kinetic. I would assume the difference in potential energies are negligible, so look at the kinetic energies.
 
  • #7
Thanks for the help!
 
  • #8
W = KE-f - KE-0
W = 1/2 m(V-f)2 - 1/2m(V-0)2
W = 0 - 1/2 * .15 * (26)2 = 50.7

D = -50.7/F = 50.7/350

?
 
  • #9
looks fine except the force was 390. If you remember kinematics, there is also an eqn;
Vf^2-Vi^2=2a*x where a would be 390/0.15

see the similarity with what you have done?
 

What is momentum?

Momentum is a physical quantity that describes the motion of an object and is defined as the product of an object's mass and velocity.

How do you calculate momentum?

Momentum (p) can be calculated as p = m * v, where m is the mass of the object and v is its velocity.

What is the unit of momentum?

The unit of momentum is kilogram-meter per second (kg·m/s).

Why does the 0.15kg ball stop at 390 N?

The 0.15kg ball stops at 390 N because 390 N is the magnitude of the force acting on the ball, which causes it to come to a halt. This could be due to an external force, such as friction or air resistance, acting on the ball.

How can momentum be conserved?

In a closed system, momentum is conserved, meaning that the total momentum before an event is equal to the total momentum after the event. This means that in order to conserve momentum, the total momentum of all objects involved in the event must remain the same before and after the event.

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