MOVIMENTO UNIFORMEMENTE VARIADO - (MUV)

Summary

This educational video explains the concept of uniformly accelerated motion, commonly found in physics exams like the ENEM. It covers the fundamentals of constant acceleration, exemplified by a car slowing down. The video introduces essential equations for solving problems in uniformly accelerated motion, such as the position equation (Sorvetão), velocity equation (Boate), and the famous Torricelli equation. Through a practical exercise involving a car's deceleration, the video demonstrates how to calculate both the time it takes to stop and the distance traveled during the deceleration. The tutorial emphasizes understanding and using multiple formulas to solve real-life physics problems effectively.

Takeaways

• 😀 Uniformly Varied Motion (MUV) refers to motion with constant acceleration.
• 😀 In MUV, the velocity increases by a constant value over time, indicating constant acceleration.
• 😀 An example of MUV: If an object starts at 0 m/s and accelerates by 3 m/s every second, the velocity changes by 3 m/s in each second.
• 😀 The acceleration in MUV is constant, and it can be calculated by the change in velocity per unit of time.
• 😀 The three key equations for solving MUV problems are: 1) Space equation (Sorvetão), 2) Velocity equation (Boate), 3) Torricelli's equation.
• 😀 The Sorvetão equation calculates space (s = s0 + v0t + ½at²), where s0 is initial position, v0 is initial velocity, a is acceleration, and t is time.
• 😀 The Boate equation calculates velocity (v = v0 + at), where v0 is initial velocity, a is acceleration, and t is time.
• 😀 Torricelli's equation (v² = v0² + 2aΔs) is used when time is not given, as it does not involve time directly.
• 😀 When solving problems involving deceleration (negative acceleration), the acceleration value is negative, indicating the opposite direction of motion.
• 😀 In a problem where a car decelerates from 20 m/s to 0 m/s at a rate of 5 m/s², the time taken to stop is 4 seconds, and the total displacement is 40 meters.

Q & A

What is uniformly accelerated motion (MUV)?

Uniformly Accelerated Motion (MUV) refers to motion where an object's acceleration is constant over time. This means the velocity of the object increases (or decreases) at a constant rate.

How is acceleration represented in MUV when an object is speeding up or slowing down?

Acceleration in MUV is represented as a constant value. If an object is speeding up, the acceleration is positive, and if it's slowing down (decelerating), the acceleration is negative, opposing the direction of motion.

What does the 'Sorvetão' equation describe, and what are the variables in it?

The 'Sorvetão' equation describes the relationship between position, velocity, and acceleration in uniformly accelerated motion. The equation is: S = S₀ + V₀t + (1/2)at², where S is the final position, S₀ is the initial position, V₀ is the initial velocity, a is acceleration, and t is time.

What is the equation of velocity (Boate), and how is it used in MUV problems?

The equation of velocity in MUV is: V = V₀ + at. It relates the final velocity (V) of an object to its initial velocity (V₀), acceleration (a), and time (t). This equation is used when solving for final velocity or when time is known.

What is Torricelli's equation, and when is it used?

Torricelli's equation is: V² = V₀² + 2aΔS. It is used when the time is not given and helps relate the final velocity (V), initial velocity (V₀), acceleration (a), and displacement (ΔS). This equation is particularly useful in problems where you need to find displacement or velocity without time.

How do you calculate time in MUV when the object is coming to a stop?

To calculate time when an object is coming to a stop, use the velocity equation V = V₀ + at. Set the final velocity (V) to 0, and solve for time (t). For example, if the object is slowing down, the acceleration will be negative.

In the example problem, why is the acceleration negative?

In the example, the car is decelerating (slowing down), so the acceleration is in the opposite direction of the motion. Since the car is moving to the right and decelerating, the acceleration is represented as negative.

How do you solve for displacement when time is known in MUV?

To solve for displacement (ΔS) when time is known, use the 'Sorvetão' equation: ΔS = V₀t + (1/2)at². Substitute the known values for initial velocity, time, and acceleration to find the displacement.

What does it mean when the problem asks for displacement without giving the time?

When the problem asks for displacement without providing time, you can use Torricelli's equation: V² = V₀² + 2aΔS. This allows you to find displacement using initial and final velocities and acceleration, without needing the time variable.

Can you always use either the Sorvetão equation or Torricelli's equation to solve MUV problems?

While you can often use either the Sorvetão or Torricelli's equation, the choice depends on the given information. If time is provided, the Sorvetão equation is appropriate. If time is not provided, Torricelli’s equation is preferred, as it doesn't require time.