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 'Rolling without slipping on a curved surface'

Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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

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