Question

Select one of the equations below to help you answer questions 18-20. $$ \text { time }=\text { distance } \div \text { speed } $$ or speed \(=\) distance \(\div\) time A typical ornithopod (plant-eating dinosaur that walked on two legs) probably moved at a speed of about \(2 \mathrm{~m} / \mathrm{s}\). How long would it take this dinosaur to run \(200 \mathrm{~m}\) ?

Short answer

It takes 100 seconds for the dinosaur to run 200 meters at 2 m/s.

Step-by-step solution

Identify What We Need to Find

We need to calculate the time it takes for the dinosaur to run a given distance. This requires using the equation that involves time, distance, and speed.

Select the Correct Equation

To find the time, we should use the equation: \[time = \frac{\text{distance}}{\text{speed}} \]This equation will allow us to solve for the time given the distance and speed.

Insert the Known Values into the Equation

We know the distance is \(200 \text{ meters}\) and the speed is \(2 \text{ meters per second}\). Substitute these values into the equation:\[time = \frac{200}{2} \]

Calculate the Time

Perform the division to find the time:\[time = \frac{200}{2} = 100 \]This means the dinosaur would take 100 seconds to run 200 meters.

Key concepts

Speed

Understanding speed is essential in physics as it helps us determine how quickly an object moves. In simple terms, speed is the distance traveled divided by the time it takes to travel that distance. It's like asking how fast something is going.
To calculate speed, we use the formula:

• Speed = Distance ÷ Time

Here are some key points about speed:

• Always measure speed in units of distance per time. Common units include meters per second (m/s) or kilometers per hour (km/h).
• Speed does not take direction into account. This means it's a scalar quantity, in contrast to velocity, which does include direction.
• When you know the speed and the distance, you can easily find the time it will take to travel that distance using rearranged versions of the same formula.

Speed is a fundamental concept that lets you understand how quickly things are moving, whether it’s a vehicle, a person, or even a dinosaur!

Distance

The concept of distance is all about understanding how far apart two points or locations are. We use distance to measure the space between various places, which can be in any direction.
The important thing about distance includes:

• Distance is a scalar quantity, meaning it only has magnitude and no direction.
• It's typically measured in units like meters (m), kilometers (km), or miles (mi).
• It forms part of the basic equation that connects it with speed and time: \[Distance = Speed \times Time\]

Using this formula, you can find how far something will travel if you know its speed and how long it's moving.
Whether you're calculating the journey of a rocket or the everyday walk of a dinosaur, understanding distance is key in putting the picture together about movement in physics.

Time

In physics, time is a crucial element to understand when you're discussing movement and change. It tells us how long an event or action takes.
Here's what you need to know about time:

• Time is often measured in seconds (s), minutes (min), or hours (h).
• It's important to keep consistent units when calculating problems involving distance and speed. For instance, when using speed in meters per second (m/s), time should be in seconds.
• The formula linking time to speed and distance is:\[Time = \frac{\text{Distance}}{\text{Speed}}\]Using this formula, as seen in the dinosaur problem, when you divide the distance by speed, you find how long a particular journey will take.

Time helps us not just in tracking an event but also in predicting how long future events might take. Knowing time helps us organize and understand motion in a structured way, making it an indispensable part of physics.