How Do You Calculate Acceleration and Velocity in Physics Problems?

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SUMMARY

The discussion focuses on calculating acceleration and velocity for a motor car traveling 1.5 meters in 1.2 seconds across a table. The acceleration is determined to be 2.1 m/s², derived from the kinematic equation for uniform acceleration. The final velocity after traveling 1 meter is calculated to be 2.5 m/s, assuming the car starts from rest. The key equations used include speed = distance/time and the appropriate kinematic equations for uniformly accelerated motion.

PREREQUISITES
  • Understanding of kinematic equations for uniformly accelerated motion
  • Basic knowledge of physics concepts such as acceleration and velocity
  • Ability to perform calculations involving distance, time, and speed
  • Familiarity with the concept of initial conditions in motion problems
NEXT STEPS
  • Study the kinematic equations, particularly those relating to acceleration and velocity
  • Learn how to derive acceleration from distance and time using the formula a = (v_f - v_i) / t
  • Explore examples of motion problems involving initial velocity and acceleration
  • Practice calculating average speed and instantaneous speed in various scenarios
USEFUL FOR

This discussion is beneficial for parents assisting their children with physics homework, students learning about motion, and educators seeking to clarify concepts of acceleration and velocity in practical applications.

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Homework Statement



I'm trying to solve the following problem to help my son with his homework...

Suppose you build a motor car that travels across a table top a distance of 1.5 meters in 1.2 seconds. The table is 0.8 m tall. The mass of the car is 300 grams. Ignore friction, air resistance.
1) If we assume that its acceleration is uniform, what is the acceleration of the car while rolling on the table? The correct answer is 2.1 m/s/s...but i don't understand how that answer was arrived at.

2) What would be the velocity of the car after it has accelerated across the table top for the distance of 1 meter? The correct answer 2.5 m/s...but once again, I don't understand it. Any help for the weary mom?


Homework Equations



speed = distance/time


The Attempt at a Solution




1.5/1.2
 
Last edited by a moderator:
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speed = distance/time

That would apply if the speed was same during the travel. speed/time, in this problem, would only result in the average speed.

Given distance and time, which of the kinematic equations would you use to find the acceleration?

(I guess the you've to assume that the car starts from rest)
 

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