How to Solve the Impulse Problem with a 70-g Steel Ball in Contact with a Plate

  • Thread starter Thread starter preluderacer
  • Start date Start date
  • Tags Tags
    Impulse
AI Thread Summary
A 70-g steel ball falls and strikes a steel plate, remaining in contact for 0.5 ms before rebounding elastically. The total round trip time for the ball is 2.00 seconds, allowing for the neglect of the brief contact time when calculating impact velocity. The velocity upon impact is approximately 9.8 m/s, and the ball rebounds at the same speed due to elastic collision. The change in momentum is crucial for determining the average force exerted during contact, which involves careful attention to vector direction. Understanding impulse and momentum is key to solving the problem accurately.
preluderacer
Messages
83
Reaction score
0

Homework Statement



A 70-g steel ball is released from rest and falls vertically onto a steel plate. The ball strikes the plate and is in contact with it for 0.5 ms. The ball rebounds elastically, and returns to its original height. The time interval for a round trip is 2.00 s. In this situation, the average force exerted on the ball during contact with the plate is closest to:



The Attempt at a Solution



Im not sure about a lot in this problem. Do I calculate the velocity has it falling for 1 sec or .75 sec or I shouldn't need to do that? I am so confused on this one.
 
Physics news on Phys.org
I don't get why do you have those 2.00 s here. What is balls velocity when it hits the plate? When it re-bounces? How is change in momentum related to to impulse?
 
So does it fall down in 1 sec? Is it then moving at 9.8 m/s. Does it then go up at 9.8 m/s?
 
preluderacer said:
Do I calculate the velocity has it falling for 1 sec or .75 sec or I shouldn't need to do that?
You're told that the total round trip time is 2.00 s and that the time in contact with the floor is 0.5 ms, so as far as computing the speed as it hits the floor you can safely neglect that 0.5 ms.

preluderacer said:
So does it fall down in 1 sec? Is it then moving at 9.8 m/s. Does it then go up at 9.8 m/s?
Yes.
 
so what I did was have (0.070kg(9.8m/s)-0.070kg(9.8m/s) / 0.005 s ? This seems very wrong to me
 
preluderacer said:
so what I did was have (0.070kg(9.8m/s)-0.070kg(9.8m/s) / 0.005 s ? This seems very wrong to me
Careful with signs. Momentum is a vector--direction matters.
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Similar threads

Solve Impulse Force Problem: 75g Ball Dropped from 2.2m
Replies
8
Views
5K
Impulse-steel ball dropped on steel slab
Replies
4
Views
4K
Impulse Word Problem: Find Momentum & Impulse
Replies
1
Views
7K
Impulse steel ball falling on steel slab
Replies
4
Views
17K
Calculating the Impulse of a dropped ball
Replies
21
Views
12K
How Do You Calculate the Impulse Exerted by the Wall on a Ball?
Replies
3
Views
3K
How to find the acceleration of a rebounded ball?
Replies
17
Views
2K
Solving Momentum and Impulse: Tennis Ball Force & Velocity
Replies
2
Views
2K
What is the average force exerted on a bouncing steel ball?
Replies
8
Views
4K
Momentum hw problem, steel ball dropped from h
Replies
1
Views
4K

Hot Threads

Recent Insights

Back
Top