Calculus 1 : How to find distance

Study concepts, example questions & explanations for Calculus 1

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Example Questions

Example Question #61 : Distance

A boat has a velocity defined by the equation . How much distance does it cover between  and ?

Possible Answers:

Correct answer:

Explanation:

In order to find the distance travelled between  and , we need to take the definite integral of the velocity 

Let's first define the definite integral as 

 for a continuous function  over a closed interval  with an antiderivative .

Using the inverse of the power rule 

 

with a constant  and , we can therefore determine that 

 

Completing the integral:

.

Example Question #61 : Distance

 

 

A particle starts at the origin and has velocity:

.

How far does it travel in the first five seconds? (Hint: this question is not asking for the distance between the starting point and the endpoint, it is asking for the total distance traversed).

Possible Answers:

Correct answer:

Explanation:

First, we must will figure out the particle's position with respect to time by integrating  with respect to . This gives us:

.

We know that  because we start at the origin. Thus,

.

This is a quadratic equation, so we know it has one local extrema. We can solve for this by settings its derivative equal to 0:

Solving this tells us that the extrema is at . Plugging this into  tells us that the particle is at  when it turns around. So we know that it starts at  moves to  and then turns around. After it turns around it goes to

.

This means it travels another  units.

Therefore, its total distance traveled is

 units.

 

Example Question #63 : Distance

Find the distance that the object has travelled in  seconds given the initial velocity and acceleration.

Possible Answers:

Correct answer:

Explanation:

We integrate the acceleartion function and use the inital velocity to find the velocity function:

We can now either choose to find the position function or take the definite integral of the velocity function over the given time interval to find the distance directly. Since we are not given the initial position, this is the natural approach.

Example Question #64 : Distance

A ball is thrown upwards at a speed of  from a  building. Assume gravity is .

What is the approximate total distance the ball has travelled (up and down) from its point of release to its impact with the ground?

Possible Answers:

Correct answer:

Explanation:

The max height of the ball happens when the velocity is zero. Using our equation, 

 we can solve for the value of  for which the velocity is zero. 

This occurs at approximately . When , the height of the ball is .

This means the ball travels  meters up from the throw at the top of the building and then drops  to the ground, for a total of  travelled.

Example Question #61 : How To Find Distance

A t-shirt is fired from a t-shirt cannon positioned high above a crowd at a concert. The t-shirt is fired horizontally with a velocity of .

How many meters does the t-shirt travel from the base of the t-shirt cannon before it hits the ground?

Possible Answers:

Not enough information

Correct answer:

Not enough information

Explanation:

You cannot determine this without knowing how high the cannon is when it fires the t-shirt.

Example Question #61 : Distance

A t-shirt is fired from a t-shirt cannon positioned high above a crowd at a concert. The t-shirt is fired horizontally with a velocity of .

Supposing the cannon is  above the ground. How many meters does the t-shirt travel laterally before hitting the ground?

Possible Answers:

 

 

Correct answer:

 

Explanation:

The t-shirt has no vertical velocity and initial height  so its vertical position is given by the function 

.

We can find the amount of time the t-shirt is airborn by setting .

We can make things a bit easier on ourselves by approximating

 and then set that expression equal to zero.

This gives us   seconds to reach the ground. Multiply this by the horizontal velocity  to get the horizontal distance travelled, which is  meters.

Example Question #61 : How To Find Distance

How far has Megan displaced from her original position (her position at ) after five seconds if her velocity as a function of time can be described by ? Assume  and  are positive constants.

Possible Answers:

Not enough information

Correct answer:

Explanation:

Her position as a function of time is just the integral of her , using the following rule,

 on each term we arrive at the position function which is,

 .

Between  and , she's displaced  units. 

This can be simplified to .

Example Question #68 : Distance

Given that the velocity of a bird flying is given as , calculate how far the bird has traveled from  to .  The original position of the bird is unknown.

Possible Answers:

None of the above.

Correct answer:

Explanation:

To solve this problem, it is important to understand that the derivative of position is velocity. Thus by integrating the velocity function, we will be able to obtain the posiiton function.  Because the problem asks us to find the distance the bird travels from  to , we integrate from 0 to 3.  The general formula for integration is

 where C can be any real number.  

Integrating the velocity function gives us 

, where C is any real number.  

However, the problem asks us the position change of the bird from   to , therefore the position of the bird is  at   and  at .  By subtracting, we get that the distance travelled by the bird during this time interval is .

Example Question #61 : Distance

What is the distance travelled by the particle from   to  if .

Possible Answers:

Correct answer:

Explanation:

We must first determine where the particle stops and turns around.

We do this by setting the first derivative, or velocity, equal to zero.

This yields .

Because  for  and

 for .

the distance travelled is

.

Example Question #70 : Distance

The velocity of a hockey puck is described by the following equation:

What is the total distance the puck travelled from  to ?

Possible Answers:

Correct answer:

Explanation:

The total distance the puck travelled during the time interval t=1 to t=9 is given by the integral of the absolute value of the velocity equation over the given time interval: .

First, one must remove the absolute value from the integral by determining the intervals where the function is positive and negative. The critical values of the function (where it equals zero) are t=6 and t=8. On the interval [1,6) the function is positive, on the interval (6,8) the function is negative, and on the interval (8, 9] the function is positive. One can determine this by plugging in any number on the given interval into the function and seeing if the output is positive or negative. Now the original integral can be broken into three integrals: 

Note that the second integral has a negative sign in front. This is to account for the fact that the function is negative from t=6 to t=8, and we are solving for total distance, not displacement.

The integration of the function is:  , which comes from the rules  and .

To evaluate the function on each interval, one must plug the upper limit of integration into the function   and then subtract by the function when the bottom limit of integration is plugged in  .

Perform this operation for each of the three integrals, and the answer is 

 

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