Car goes off cliff question

• loganblacke
In summary, the problem involves a car parked on an incline with a 15.6 degree angle, rolling down and off a cliff 57m above the ground. The goal is to find the car's position when it reaches the ground relative to the base of the cliff. The method used is kinematics and the key equation used is v^2=u^2+2as. After some calculations, the final velocity of the car when it reaches the ground is found to be 12.04 m/s. However, there seems to be an error in the calculation as the answer is not correct.

Homework Statement

A car is parked on an incline of 15.6 degrees below the horizontal, the brakes fail and it rolls down the incline 27.5m and off the edge of a cliff that is 57m above the ground. Find the car's position when it its the ground relative to the base of the cliff.

Homework Equations

rather than type them all out, I'll just say kinematics.

The Attempt at a Solution

I know you have to break the gravity vector up into components so I took -9.8 sin(15.6) = -2.63 m/s^2. I keep calculating the average speed of the car, not the speed at the point it goes off the cliff. Please help, thanks!

v^2=u^2+2as, so the car is traveling at (2*9.8sin(15.6)*27.5)^0.5 when it goes off the cliff.

You have not said enough. You keep calculating the average speed. Do you want to calculate the average speed? Could you use the average speed? What is your plan for this question?

cosmo123 said:
v^2=u^2+2as, so the car is traveling at (2*9.8sin(15.6)*27.5)^0.5 when it goes off the cliff.

Thanks, but I'm still getting the wrong answer. I end up with the velocity of the car being 12.04 m/s when it leaves the cliff. So initial velocity in the y direction when the car leaves the cliff should be 12.04*sin(15.6) = 3.24. Plug that into y=Vi(t)-4.92(t)^2 to solve for t. End up with 57 = 3.24(t) - 4.92(t)^2.. rewritten in quadratic form.. 4.92t^2-3.24t-57=0. then t = 3.748 seconds which is not correct.

vertigo said:
You have not said enough. You keep calculating the average speed. Do you want to calculate the average speed? Could you use the average speed? What is your plan for this question?

How is that not enough information? You have a car rolling down a slope then off a cliff. You obviously need to know the velocity of the car as it rolls of the cliff to answer the question. I calculated the acceleration but couldn't remember how to get Vfinal.

1. How does the car go off the cliff?

The car most likely goes off the cliff due to driver error or mechanical failure. This could include distracted driving, loss of control, or faulty brakes.

2. What are the potential consequences of a car going off a cliff?

The consequences of a car going off a cliff can be severe, including injury or death to the driver and passengers, damage to the vehicle, and impact on the surrounding environment.

3. Can a car survive going off a cliff?

In some cases, a car may survive going off a cliff depending on the height and angle of the fall, as well as the make and model of the vehicle. However, it is important to note that even if the car survives, the passengers may still sustain serious injuries.

4. What factors can contribute to a car going off a cliff?

There are several factors that can contribute to a car going off a cliff, including road conditions, weather, driver behavior, and vehicle maintenance. It is important for drivers to be aware of these factors and take necessary precautions to prevent accidents.

5. How can we prevent cars from going off cliffs?

To prevent cars from going off cliffs, it is essential for drivers to practice safe driving habits such as staying focused, following speed limits, and properly maintaining their vehicles. Additionally, roads and highways should be designed and maintained with safety in mind.