Determine the velocity of the car after it has been floored for 8 seconds

Click For Summary
To determine the velocity of a car after 8 seconds of acceleration, the mass is 1200 kg, and the engine exerts a constant force of 9600 N while facing a drag force represented by D=160v. The equation of motion is m(dv/dt) = 9600 - 160v, which can be rearranged for integration. By substituting u=60-v, the left side can be integrated, leading to a solution for velocity over time. Understanding the integration process is crucial for solving the problem accurately.
2Pac
Messages
37
Reaction score
0
Hey if anyone could please tell me how to do this it would be a great help.

ok the question asks about an accelerating car. The mass of the car is 1200kg. When the engine is floored it creates a constant forward force of 9600N. The drag created by the car is equal to this equation: D=160v. Determine the velocity of the car after it has been floored for 8 seconds.
 
Physics news on Phys.org
You just need to solve the equation of motion:

m\frac {dv}{dt} = 9600 - 160 v

Just remember to keep your units consistent!
 
actually i am not familiar with that equation. and my calculus is poor. So if anyone could explain this further, thanks!
 
1200\frac {dv}{dt} = 9600 - 160 v= 160(60- v)
is the same as
\frac{dv}{60-v}= \frac{160}{1200}dt= \frac{1}{20}dt

To integrate the left side, let u= 60- v so that du= -dv and the equation becomes
-\frac{du}{u}= \frac{1}{20}dt

You ought to be able to integrate that.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

  • · Replies 29 ·
Replies
29
Views
4K
Replies
11
Views
2K
  • · Replies 48 ·
2
Replies
48
Views
9K
Replies
4
Views
3K
  • · Replies 4 ·
Replies
4
Views
7K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 5 ·
Replies
5
Views
8K
  • · Replies 15 ·
Replies
15
Views
2K
Replies
14
Views
3K