GCSE Physics Tutorial: Calculating Change in Momentum from a Force Applied over Time
Calculating the change in momentum from a force applied over a specific time interval is a fundamental skill that helps us understand the effects of forces on an object's motion. This concept is crucial for comprehending how forces cause changes in velocity and momentum. In this tutorial, we'll guide you through the process of calculating the change in momentum using the impulse equation.
The Impulse Equation:
The impulse equation relates the change in momentum ($Δp$) of an object to the force ($F$) applied to it and the time interval ($Δt$) over which the force is applied. Mathematically, the equation is expressed as:
$Δp=F⋅Δt$
Where:
$Δp$ represents the change in momentum of the object.
$F$ is the force applied to the object.
$Δt$ is the time interval over which the force is applied.
Steps to Calculate Change in Momentum:
To calculate the change in momentum from a force applied over a specific time interval, follow these steps:
Identify Values: Determine the force ($F$) applied to the object and the time interval ($Δt$) over which the force is applied.
Apply Impulse Equation: Substitute the values of force and time interval into the impulse equation ($Δp=F⋅Δt$).
Perform Calculation: Multiply the force ($F$) by the time interval ($Δt$) to find the change in momentum ($Δp$).
Include Units: Ensure that the units of force are newtons (N) and the unit of time is seconds (s) to obtain the correct unit for change in momentum (kg m/s).
Example Calculation:
Let's work through an example:
A tennis player hits a ball with a force of 100 N over a time interval of 0.02 seconds. Calculate the change in momentum of the ball.
Identify Values: $F=100N$, $Δt=0.02s$.
Apply Impulse Equation: $Δp=100⋅0.02$.
Perform Calculation: $Δp=2N s$.
Implications and Applications:
Calculating the change in momentum using the impulse equation helps us understand the effects of forces on objects in motion.
Real-World Application:
This skill finds application in analysing sports movements, engineering designs, and predicting the outcomes of various force-related scenarios.
Summary:
Calculating the change in momentum from a force applied over a specific time interval involves identifying force and time values, applying the impulse equation ($Δp=F⋅Δt$), performing the calculation, and including the appropriate units. This skill is essential for understanding how forces impact an object's motion and momentum.
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