2 Part Kinematic Equation Problem

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In summary, two cars are involved in a chase, one traveling at a constant speed of 75 ft/s and the other initially at rest. The police car accelerates at a rate of 12.50 ft/s in order to catch up with the first car in 12 seconds. At the end of the 12 seconds, the police car's speed is 150 ft/s. The kinematic equations are used to solve for the displacement and final velocity of the police car.
  • #1
demonslayer42
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Homework Statement


A car driving at a constant speed of 75 ft/s passes a police car that is initially at rest. If the police car decides to give chase
A) What rate would the police have to accelerate to catch up with the other car in 12 seconds?
B) What is the police car's speed at the end of the 12 seconds?


Homework Equations


Use Kinematic Equations


The Attempt at a Solution


The first car's displacement would be 75 ft/s * 12 seconds = 900 feet? So if I use X = Vot + 1/2(at^2)that means that acceleration of the second car would have to be 12.50 ft/s Is this the correct? Or am I way off? So if the acceleration = 12.50 ft/s I use V = Vo + at and end up with Final V = 150 ft/s ? That just doesn't sound right to me, could you please try to explain what I'm doing wrong?
 
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  • #2
Looks good to me. You're doing nothing wrong.
 
  • #3
Well thank you :) I'm trying really hard to learn Physics. It's difficult for me to learn, but it's very interesting.
 

FAQ: 2 Part Kinematic Equation Problem

What are the two parts of the kinematic equation?

The two parts of the kinematic equation are distance and time. Distance is the physical length travelled by an object, while time is the duration of the motion.

What is the formula for solving a 2 part kinematic equation problem?

The formula for solving a 2 part kinematic equation problem is: d = v0t + 1/2at2, where d is the distance, v0 is the initial velocity, a is the acceleration, and t is the time.

How do you determine the initial velocity in a 2 part kinematic equation problem?

The initial velocity (v0) can be determined by using the formula: v0 = d/t - 1/2at, where d is the distance, t is the time, and a is the acceleration.

What is the difference between average velocity and instantaneous velocity?

Average velocity is the overall velocity of an object over a specific time period, while instantaneous velocity is the velocity of an object at a specific moment in time. Average velocity is calculated by dividing the total distance travelled by the total time taken, while instantaneous velocity is calculated by taking the derivative of the displacement-time graph at a specific point.

How do you calculate acceleration in a 2 part kinematic equation problem?

Acceleration can be calculated by using the formula: a = 2(d - v0t)/t2, where d is the distance, v0 is the initial velocity, and t is the time. Alternatively, acceleration can also be determined by finding the slope of the velocity-time graph.

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