Solving Momentum and Speed: 1500kg Car Moves 25 m/s

  • Thread starter Thread starter Husker70
  • Start date Start date
  • Tags Tags
    Momentum Speed
AI Thread Summary
A 1500kg car has the same momentum as a 2500kg truck moving at 15 m/s, resulting in a momentum calculation of 37500 kg·m/s for both vehicles. The car's speed is determined using the formula v = p/m, which calculates to 25 m/s when substituting the momentum and mass of the car. Despite this calculation, the answer was marked incorrect, leading to confusion among participants. Some believe the initial calculation is correct, while others suggest there may be additional context or information affecting the answer. The discussion highlights the importance of clarity in problem statements and the potential for miscommunication in academic settings.
Husker70
Messages
89
Reaction score
0

Homework Statement


A 1500kg car has the same momentum as a 2500kg truck moving at 15 m/s.
How fast is the car moving?
A. 15 m/s
B. 25 m/s
C. 35 m/s
D. 40 m/s
E. 50 m/s

Homework Equations


p = mv


The Attempt at a Solution


Truck = (2500kg)(15m/s) = 37500
Car = v=p/m = 37500/1500kg = 25m/s

This is what I answered but it says it wrong.
Any help would be appreciated.
Kevin
 
Physics news on Phys.org
Husker70 said:

Homework Statement


A 1500kg car has the same momentum as a 2500kg truck moving at 15 m/s.
How fast is the car moving?
A. 15 m/s
B. 25 m/s
C. 35 m/s
D. 40 m/s
E. 50 m/s

Homework Equations


p = mv


The Attempt at a Solution


Truck = (2500kg)(15m/s) = 37500
Car = v=p/m = 37500/1500kg = 25m/s

This is what I answered but it says it wrong.
Any help would be appreciated.
Kevin

You're not wrong unless you're leaving out some information.
 
I've got everything. We took a test and get to retake it. I missed this one by putting 25 m/s. I think it's right. I emailed my instructor.
Thanks,
Kevin
 
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 »

Similar threads

How to solve for the distance traveled given force, mass and speed
Replies
4
Views
2K
Momentum: instantaneous or average?
Replies
9
Views
1K
Distance traveled during a head on collision
Replies
36
Views
6K
What is the initial momentum of the car and rider in a collision?
Replies
2
Views
2K
Car Crash Analysis: Analyzing Friction & Speed
Replies
9
Views
4K
Momentum, collision of two cars problem
Replies
5
Views
6K
How Fast Was the Car Moving in the Radar Speed Trap Experiment?
Replies
8
Views
3K
Speed of Truck Relative to Highway: Solving the Puzzle
Replies
7
Views
6K
Finding the total momentum of system
Replies
8
Views
3K
What Is the Speed of Five Coupled Freight Cars After a Collision?
Replies
4
Views
2K

Hot Threads

Recent Insights

Back
Top