Center of Mass and car inertia

In summary, the primary reason for the front of a car lifting or dipping during acceleration or braking is because the center of mass of the car and its contents is positioned above the road. This is due to the force applied along the surface of the road, which results in torque acting in the direction of the wheel's axis. The correct answer is D, center of mass of the car and its contents is above the road.
  • #1
Kavorka
95
0
I got one multiple choice on our exam incorrect, and I was wondering exactly why this answer is correct:

When you accelerate your car, the front of the car lifts up slightly. Or when you brake, the front dips down. The primary reason is because the
A) center of mass of the car and its contents is below the center of the wheel.
B) center of mass of the car and its contents is above the center of the wheel.
C) center of mass of the car and its contents is at the center of the wheel.
D) center of mass of the car and its contents is above the road.
E) car has inertia.

E is a bit of a default answer because it can be explained by inertia, and that's what I said. A and C can be ruled out. I was pondering B and D far too long which is why I defaulted to E, but the correct answer is D. Why is this?
 
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  • #2
Kavorka said:
I got one multiple choice on our exam incorrect, and I was wondering exactly why this answer is correct:

When you accelerate your car, the front of the car lifts up slightly. Or when you brake, the front dips down. The primary reason is because the
A) center of mass of the car and its contents is below the center of the wheel.
B) center of mass of the car and its contents is above the center of the wheel.
C) center of mass of the car and its contents is at the center of the wheel.
D) center of mass of the car and its contents is above the road.
E) car has inertia.

E is a bit of a default answer because it can be explained by inertia, and that's what I said. A and C can be ruled out. I was pondering B and D far too long which is why I defaulted to E, but the correct answer is D. Why is this?
Where is the force which changes the car's velocity applied ?
 
  • #3
Along the surface of the road?
 
  • #4
Kavorka said:
Along the surface of the road?
Yes.
 
  • #5
How does that result in the lifting or dipping of the front of the car when there is acceleration
 
  • #6
Kavorka said:
How does that result in the lifting or dipping of the front of the car when there is acceleration
What do you know about torque?
 
  • #7
It would be acting in the direction of the wheel's axis.
 

1. What is the center of mass of a car?

The center of mass of a car is the point at which the entire weight of the car can be considered to be concentrated. This point is determined by the distribution of the car's mass, and can change depending on the position of the car and its contents.

2. How is the center of mass of a car calculated?

The center of mass of a car can be calculated by finding the average position of all the individual particles that make up the car, weighted by their mass. This can be done using mathematical equations or through physical experiments.

3. Why is the center of mass important in car design?

The center of mass is important in car design because it affects the car's stability, handling, and overall performance. A lower center of mass can improve a car's stability and cornering abilities, while a higher center of mass can make it more prone to tipping over.

4. How does the center of mass affect a car's inertia?

The center of mass and inertia are directly related. The further the center of mass is from the axis of rotation, the greater the car's moment of inertia will be. This means it will require more force to change the car's rotational motion.

5. Can the center of mass of a car be changed?

Yes, the center of mass of a car can be changed by altering the distribution of its mass. This can be done by adding or removing weight from different areas of the car, or by changing the position of heavy objects such as the engine or fuel tank.

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