Solve Momentum Question: 5kg Object, 15 kg m/s, 8 m/s in 15s

  • Thread starter Thread starter zaga04
  • Start date Start date
  • Tags Tags
    Momentum
AI Thread Summary
To determine the net force required to accelerate a 5kg object from its initial momentum of 15 kg m/s to a final velocity of 8 m/s over 15 seconds, the correct approach involves calculating the change in momentum. The formula F = deltaP/deltaT is applicable, where deltaP is the change in momentum and deltaT is the time interval. The initial momentum is 15 kg m/s, and the final momentum can be calculated using the mass and final velocity. The discussion highlights confusion regarding the correct application of formulas, emphasizing that acceleration should consider the initial velocity due to the object's existing momentum. Ultimately, the net force needed can be calculated accurately using the proper momentum change.
zaga04
Messages
15
Reaction score
0

Homework Statement


1. A 5kg object has a momentum of 15 kg m/s. What is the net force required to accelerate the object to 8 m/s over 15 seconds?
A) .35N
B) 1.7N
C) 5.1 N
D) 11 N
E) 23 N


Homework Equations


F=deltaP/deltaT


The Attempt at a Solution


So I use that formula (which I am not sure is right). so wouldn't it be mv/t. So, (5)(8)/15 which is 2.67N which is not an answer choice.

I think I am using the wrong formula, but it's all I can think of! Please help.
 
Physics news on Phys.org
The acceleration is not v/t in this case. The object has initial velocity because its momentum is 15 kg m/s before it starts accelerating.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

How Does Impulse Relate to Momentum Change in Physics Problems?
Replies
7
Views
2K
Momentum, collision of two cars problem
Replies
5
Views
6K
Mass of Object Pulled by 40 HP Engine: 1,350 Kg
Replies
1
Views
1K
What is the final angular displacement of a disk hit by two masses?
Replies
3
Views
2K
Conservation of Momentum (Explosion Kinematics)
Replies
15
Views
2K
Calculate the change in mechanical energy during collision
Replies
16
Views
2K
How do we know how long the force is acting on an object?
Replies
4
Views
2K
A ball is thrown up at 20 m/s at an agle of 15 degrees
Replies
7
Views
2K
Impulse and Average Force. Ball by the Wall.
Replies
5
Views
6K
A car is heading 43 m/s east. Find momentum, velocity
Replies
4
Views
2K

Hot Threads

Recent Insights

Back
Top