How to Calculate Speed and Velocity in Your Physics Projects

When you're studying Kinematics in Grade 10 Physics, it's super important to know about speed and velocity. Both terms relate to how things move, but they mean different things and need different calculations.

What Do Speed and Velocity Mean?

• Speed is all about how fast something is moving. It tells you the distance traveled in a certain amount of time. Speed doesn’t say anything about the direction the object is moving.

  The formula for speed is:

  $\text{Speed (v)} = \frac{\text{Distance (d)}}{\text{Time (t)}}$

• Velocity, on the other hand, tells you how fast something is moving and in which direction. So, velocity includes both speed and direction.

  The formula for velocity is:

  $\text{Velocity (v)} = \frac{\text{Displacement (s)}}{\text{Time (t)}}$

  Displacement is just the straight-line distance from where the object started to where it ended up.

Main Differences Between Speed and Velocity:

1. Type:

   • Speed: Scalar (just a number)
   • Velocity: Vector (a number and a direction)

2. What They Include:

   • Speed: Only how fast it is (like 50 km/h)
   • Velocity: How fast it is and where it's going (like 50 km/h north)

3. How They Can Be Measured:

   • Speed can be average (over time) or instantaneous (right now).
   • Velocity can also be average or instantaneous, and it tells you about direction changes.

How to Calculate Speed and Velocity:

Here’s how you can figure out speed and velocity for your projects:

1. Get Your Data:

   • Measure how far the object travels if you're looking for speed.
   • For velocity, measure how far the object moved from start to finish.
   • Use a stopwatch to time how long it takes.

2. Calculating Speed:

   • Use the speed formula. For example, if a car goes 150 km in 3 hours, the average speed is:

   $\text{Speed} = \frac{150 \text{ km}}{3 \text{ hours}} = 50 \text{ km/h}$

3. Calculating Velocity:

   • For velocity, remember to include the direction. If the car traveled 150 km east in those 3 hours, the average velocity would be:

   $\text{Velocity} = \frac{150 \text{ km east}}{3 \text{ hours}} = 50 \text{ km/h east}$

Example Project:

Let’s say you are working on a project where you watch a toy car move on a straight track:

• Measure the distance the toy car goes (like 100 meters).
• Use a stopwatch to see how long it takes (like 5 seconds).

To Calculate Speed: $\text{Speed} = \frac{100 \text{ m}}{5 \text{ s}} = 20 \text{ m/s}$

To Calculate Velocity (if the car moves to the right): $\text{Velocity} = \frac{100 \text{ m to the right}}{5 \text{ s}} = 20 \text{ m/s right}$

In short, by measuring distance and time carefully, and knowing the difference between speed and velocity, you’ll better understand how things move in physics. These concepts will help you analyze and report your project results accurately.