How does initial velocity affect a car's stopping distance?

  • Thread starter Thread starter public_enemy720
  • Start date Start date
  • Tags Tags
    Braking System
AI Thread Summary
The discussion focuses on how initial velocity influences a car's stopping distance. A car traveling at 7 m/s slides 1.5 meters before stopping, while at 14 m/s, it would slide approximately 6.01 meters under the same braking force. The key equation used is v^2 = Vo^2 + 2(a)(S-So), which relates initial velocity, final velocity, acceleration, and distance. The acceleration calculated is -16.3 m/s^2, confirming that doubling the velocity results in a stopping distance that is four times greater. This illustrates the quadratic relationship between initial velocity and stopping distance.
public_enemy720
Messages
4
Reaction score
0
A car is traveling at 7 m/s when the wheels are locked up. The car slides 1.5 meters before coming to rest. If the car had been moving at 14 m/s, how far would the car slide, assuming the same breaking force is used?

Not sure where to go with this problem...
 
Physics news on Phys.org
Hint: Which of the equations of motion relates initial velocity, final velocity, acceleration, and distance moved?
 
I used the equation v^2=Vo^2+2(a)(S-So) and solved for acceleration, then plugged in new value for initial velocity and used the found acceleration. Is this correct?

accel. = -16.3m/s^2
distance traveled @ 14 m/s = 6.01 m
 
public_enemy720 said:
I used the equation v^2=Vo^2+2(a)(S-So) and solved for acceleration, then plugged in new value for initial velocity and used the found acceleration. Is this correct?

accel. = -16.3m/s^2
distance traveled @ 14 m/s = 6.01 m
Close enough, and that's exactly the correct approach. Since the velocity doubled, the stopping distance would be 2^2 = 4 times as great for the same acceleration.
 
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 »

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

Final Velocity of a car with a opposing decreasing drag force
2
Replies
57
Views
2K
Problem with the power of car
Replies
3
Views
866
Help with question on motion: Avoiding a rear-end collision
Replies
6
Views
3K
Distance travelled by a car considering only air friction?
Replies
4
Views
2K
Reaction time while stopping a car
Replies
29
Views
3K
Question about car braking and tire friction
Replies
19
Views
3K
Stopping distance of a car rolling down a hill
Replies
4
Views
2K
Solving for Car Speed and Stopping Time in a Braking Scenario
Replies
1
Views
6K
Kinematics car braking scenario
Replies
8
Views
3K
Calculating Separation of Cars in a Convoy Moving at Max Speed
Replies
4
Views
3K

Hot Threads

Recent Insights

Back
Top