Multiple choice velocity/acceleration

In summary, a strobe photograph of a car moving along a straight road shows a diminishing interval between each successive image. If the direction of motion is positive, the speed, average velocity, and average acceleration of the car are all decreasing. This is because the distance covered in the same time interval is decreasing, indicating a slowing down of the car. This can be explained using basic physics formulas such as s = vt and 1/2at^2.
  • #1
williamx11373
21
0
a strobe photograph of a car moving along a straight road shows the interval between each successive image to be diminishing. If the direction of motion of the car is taken as positive, which of the following are negative?

a. the speed of the car
b. the average velocity of the car
c. the average acceleration of the car
d. all of the above


i never learned what a strobe photograph is, but I am guessing it is C. because it is slowing down and therefore diminishing.

is that correct ?
 
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  • #2
A strobe photograph is basically an image in which multiple photos are overlayed, taken at fixed time intervals. I bet you have seen them before, like this one.

So in the question what they basically say is that the distance covered in the same time interval (say, 1 second) decreases.

Using what you know about physics (e.g. the s = v t and 1/2 a t^2 formulas for different types of motion) can you try to reason what is going on with the velocity and acceleration, and try to back your statement?
 
  • #3


Yes, that is correct. The average acceleration of the car would be negative because the car is slowing down, meaning its velocity is decreasing over time.
 

Related to Multiple choice velocity/acceleration

1. What is the difference between velocity and acceleration?

Velocity is the rate at which an object changes its position in a specific direction, while acceleration is the rate at which an object changes its velocity. In other words, velocity measures how fast an object is moving, while acceleration measures how quickly its velocity is changing.

2. How are velocity and acceleration related?

Velocity and acceleration are related by the fundamental formula of kinematics, which states that acceleration is equal to the change in velocity divided by the change in time. In other words, acceleration is the rate of change of velocity.

3. What is the difference between average and instantaneous velocity/acceleration?

Average velocity/acceleration is the total displacement/change in velocity over a given time period, while instantaneous velocity/acceleration is the velocity/acceleration at a specific moment in time. Average velocity/acceleration is calculated by dividing the total displacement/change in velocity by the total time, while instantaneous velocity/acceleration is calculated by taking the derivative of the position/velocity function at a specific time.

4. How do you calculate velocity/acceleration from a position/time graph?

Velocity can be calculated by finding the slope of the tangent line to the position/time curve at a specific point, while acceleration can be calculated by finding the slope of the velocity/time curve at a specific point. Alternatively, velocity can be calculated by taking the derivative of the position function, and acceleration can be calculated by taking the derivative of the velocity function.

5. What are some real-life examples of velocity and acceleration?

Some real-life examples of velocity include the speed of a car on a highway, the rate at which a roller coaster moves down a track, and the speed of a person running. Some real-life examples of acceleration include the force of gravity on a falling object, the acceleration of a car when the gas pedal is pressed, and the acceleration of a rocket as it launches into space.

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