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A roller coaster car traveling at a constant speed of \(20.0 \mathrm{~m} / \mathrm{s}\) on a level track comes to a straight incline with a constant slope. While going up the incline, the car has a constant acceleration of \(0.750 \mathrm{~m} / \mathrm{s}^{2}\) in magnitude. (a) What is the speed of the car at \(10.0 \mathrm{~s}\) on the incline? (b) How far has the car traveled up the incline at this time?

Short Answer

Expert verified
(a) The speed at 10.0 s is 12.5 m/s. (b) The car travels 162.5 m up the incline.

Step by step solution

01

Identify the known variables

We are given the initial velocity of the roller coaster, which is \(v_0 = 20.0\, \text{m/s}\), the acceleration while going up the incline \(a = -0.750\, \text{m/s}^2\), and the time \(t = 10.0\, \text{s}\). The acceleration is negative because it is decelerating.
02

Use the formula for final velocity

We use the equation for motion with constant acceleration: \(v = v_0 + at\). Substituting the known values, we have:\[v = 20.0\, \text{m/s} + (-0.750\, \text{m/s}^2) \times 10.0\, \text{s}\].
03

Calculate the speed at time 10.0 s

Substitute and calculate the final velocity:\[v = 20.0 - 7.50 = 12.5\, \text{m/s}\].So, the speed of the car at 10.0 seconds is \(12.5\, \text{m/s}\).
04

Use the formula for distance traveled

Use the equation for distance traveled with constant acceleration \(d = v_0 t + \frac{1}{2} a t^2\). Substituting the known values, we have:\[d = 20.0\, \text{m/s} \times 10.0\, \text{s} + \frac{1}{2} \times (-0.750\, \text{m/s}^2) \times (10.0\, \text{s})^2\].
05

Calculate the distance traveled

First calculate \(\frac{1}{2} a t^2\):\[\frac{1}{2} \times -0.750 \times 100 = -37.5\, \text{m}\].Now calculate the total distance:\[d = 200 \text{ m} - 37.5 \text{ m} = 162.5 \text{ m}\].Thus, the car travels 162.5 meters up the incline in 10.0 seconds.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Constant Acceleration
Constant acceleration occurs when an object's velocity changes at a uniform rate. In other words, the acceleration is the same throughout the motion. This means that the force acting on the object does not change, and therefore neither does the acceleration.
In our roller coaster example, the car experiences a constant acceleration of \(0.750 \, \text{m/s}^2\) while ascending the incline. Here, the negative sign indicates that the car is decelerating or slowing down as it goes upward. This negative acceleration is crucial for calculating how the car's speed changes over time and is the cornerstone behind predicting its velocity and distance traveled at a given time.
Motion Equations
Motion equations are mathematical formulas used to describe the movement of objects. These equations relate key motion variables such as displacement, velocity, acceleration, and time. They help us predict the result of one variable when others are known.
For an object moving with constant acceleration, we can use equations like:
  • Final velocity, \(v = v_0 + at\)
  • Displacement, \(d = v_0 t + \frac{1}{2} a t^2\)
In the roller coaster problem, these equations allow us to calculate both how fast the roller coaster car is moving after a certain time period (10 seconds), and the distance it has covered in that time. By plugging in known values, we see the car's speed decrease from \(20 \, \text{m/s}\) to \(12.5 \, \text{m/s}\), making these equations vital tools in understanding and predicting motion.
Inclined Plane
An inclined plane is a flat surface tilted at an angle, other than a right angle, against a horizontal surface. It helps move objects up or down with ease by reducing the effect of gravity, allowing less force to be used in moving an object when compared to lifting vertically.
When dealing with motion on an incline, friction and gravitational forces act on the object. In our exercise, as the roller coaster moves up the slope, gravity works against it, causing the car to decelerate. This explains why we have a negative acceleration in our calculations: because of the slope, gravity reduces the car's speed as it travels upward.
Understanding inclined planes is essential in physics as it introduces concepts like resolving gravitational forces into components, which play crucial roles in both theoretical problems and real-world applications like transportation systems.
Velocity Calculation
Velocity calculation is essential for determining how fast and in which direction an object moves. It is a vector quantity, meaning it has both magnitude and direction. Knowing how to calculate velocity is crucial for predicting future positions of moving objects.
In our example, the roller coaster's velocity changes over time due to constant acceleration. Using the equation \(v = v_0 + at\), we calculate how the roller coaster's initial velocity of \(20 \, \text{m/s}\) decreases to \(12.5 \, \text{m/s}\) over a period of 10 seconds on the incline. This demonstrates how velocity varies with acceleration and time, providing insights into the dynamics of moving objects across different scenarios. Understanding this concept can apply to various fields, from amusement park safety to vehicular motion on hilly terrains.

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Most popular questions from this chapter

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