Velocity, momentum car help please

In summary, this conversation is discussing a scenario in which a car with failed brakes travels off a cliff at a constant velocity of 45 m/s. The conversation then goes on to ask for the distance the car travels before hitting the ground, the deceleration of the car when it hits the ground and skids, and the velocity of the car after a collision with a stationary Honda Civic. The conversation ends with a request for tips on how to solve the problem.
  • #1
Jessicaelleig
12
0
Velocity, displacement?
Please help me to solve this! I have no idea!

The brakes of a car failed and the car travels at a constant velocity of 45 m/s off a 27 m cliff.

A) How far from the cliff does the car hit the ground?

B)When it hits the ground, it skids off 13 m/s with a coefficient of friction of 0.55. What's the deceleration of the car?

C) The car travels 5 m when it crashes into a stationary 650 kg Honda Civic. The collision is elastic. The velocity of the original car is 2 m/s after the collision. What is the velocity of the Honda Civic after the crash?

Please give me tips on how to solve this! i will give 10 points to the best answer!]
 
Physics news on Phys.org
  • #3


A) To solve for the distance traveled by the car, we can use the equation d = v^2/2a, where d is the distance, v is the initial velocity (45 m/s), and a is the acceleration due to gravity (-9.8 m/s^2). Plugging in these values, we get d = (45 m/s)^2 / (2 * -9.8 m/s^2) = 102.8 m. Therefore, the car will hit the ground 102.8 meters away from the cliff.

B) To find the deceleration of the car, we can use the equation vf^2 = vi^2 + 2ad, where vf is the final velocity (13 m/s), vi is the initial velocity (45 m/s), and d is the distance traveled (102.8 m). Rearranging this equation to solve for a, we get a = (vf^2 - vi^2) / 2d = (13 m/s)^2 - (45 m/s)^2 / (2 * 102.8 m) = -3.23 m/s^2. This is the deceleration of the car as it skids off the ground.

C) To find the final velocity of the Honda Civic, we can use the conservation of momentum equation, m1v1 + m2v2 = m1u1 + m2u2, where m1 is the mass of the original car (unknown), m2 is the mass of the Honda Civic (650 kg), v1 is the initial velocity of the original car (2 m/s), v2 is the final velocity of the Honda Civic (unknown), u1 is the initial velocity of the Honda Civic (0 m/s), and u2 is the final velocity of the Honda Civic (unknown). We can rearrange this equation to solve for v2, which gives us v2 = (m1v1 + m2u1 - m1u1) / m2 = (m1 * 2 m/s) / 650 kg. Since the collision is elastic, we know that the total momentum before and after the collision must be equal, so m1v1 = m1u1 + m2u2. Substituting this into our equation for v2, we get v2 = (m1 * 2 m/s) / 650 kg = (m1
 

1. What is velocity?

Velocity is a measure of an object's speed and direction. It is a vector quantity, which means it has both magnitude (speed) and direction.

2. How is velocity calculated?

Velocity is calculated by dividing the change in an object's position by the change in time. It is typically measured in units of meters per second (m/s).

3. What is momentum?

Momentum is a measure of an object's mass and velocity. It is a vector quantity, which means it has both magnitude (mass) and direction (velocity).

4. How is momentum related to velocity?

Momentum and velocity are directly related. Momentum is equal to an object's mass multiplied by its velocity. This means that an object with a higher velocity will have a greater momentum.

5. How can I calculate the momentum of a car?

To calculate the momentum of a car, you will need to know its mass and velocity. The equation for momentum is: momentum = mass x velocity. You can measure the mass of the car in kilograms (kg) and its velocity in meters per second (m/s).

Similar threads

  • Introductory Physics Homework Help
Replies
29
Views
2K
  • Introductory Physics Homework Help
Replies
6
Views
627
  • Introductory Physics Homework Help
Replies
6
Views
846
  • Introductory Physics Homework Help
Replies
2
Views
639
  • Introductory Physics Homework Help
Replies
7
Views
1K
  • Introductory Physics Homework Help
Replies
9
Views
965
  • Introductory Physics Homework Help
Replies
9
Views
3K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
10
Views
1K
Back
Top