QuestionA car accelerates from rest at . How much time does it need to attain a speed of ?
Answer in units of s. Answer in units of s.
Studdy Solution
STEP 1
What is this asking?
How long does it take a car starting from a standstill to reach a speed of if it's accelerating at ?
Watch out!
Don't mix up speed and acceleration; acceleration is how quickly the speed changes!
Also, remember that the car starts from rest, meaning its initial speed is .
STEP 2
1. Define Acceleration
2. Calculate the Time
STEP 3
Alright, so we know the car is accelerating at .
But what does that *really* mean?
It means that every second, the car's speed increases by .
That's our **rate of change**!
STEP 4
We can write this mathematically using the formula for acceleration:
STEP 5
Let's use variables to make things easier.
Let represent acceleration, represent the **final speed**, represent the **initial speed**, and represent the time.
So, we have:
STEP 6
We're trying to find the time , so let's **rearrange the formula** to solve for it.
We can do this by multiplying both sides of the equation by and then dividing both sides by :
STEP 7
Now we can **plug in the values** we know.
The **final speed** is , the **initial speed** is (because the car starts from rest!), and the acceleration is .
STEP 8
Let's **crunch the numbers**:
STEP 9
So, it takes approximately seconds for the car to reach a speed of .
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