Elementary physics in 1 dimension

In summary, the driver of a car wishes to pass a truck traveling at a constant speed of 19.0 m/s. The car begins accelerating at 0.550 m/s^2 and pulls back into the truck's lane when its rear is 25.4 m ahead of the truck's front. The car and truck have lengths of 4.90 m and 21.8 m respectively. The required time for the car to pass the truck is 13.5 seconds. However, this time may be interpreted differently depending on when the car is considered to have "passed" the truck.
  • #1
parm12
3
0
The driver of a car wishes to pass a truck that is traveling at a constant speed of 19.0 m/s. Initially, the car is also traveling at a speed 19.0 m/s and its front bumper is a distance 23.7 m behind the truck's rear bumper. The car begins accelerating at a constant acceleration 0.550 m/s^2, then pulls back into the truck's lane when the rear of the car is a distance 25.4 m ahead of the front of the truck. The car is of length 4.90 m and the truck is of length 21.8 m. How much time is required for the car to pass the truck?

I'm having trouble understanding why 13.5 s is incorrect.

Here is my approach:

T_position = 19(m/s)t + 50.4m (50.4 = Car length + Truck Length + Distance in beteen)
C_position = .275(m/s^2)t^2 + 19(m/s)t

C_position corresponds to the rear of the car, and T_position the front of the truck.

Solving for both position equations yields:

50.4m = .275(m/s^2)t^2

sqrt(50.4/.275) = t = 13.5s
 
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  • #2
They're probably asking when the car pulls back into the same lane as the truck. Then the car will have completed his manouver to pass the car, not when the car's rear is at the truck's front.
It isn't specifically mentioned, but from the information given in the question, it's highly certain.
 
  • #3
Correct

You were correct, but I do feel misled by the question. The time it takes a particle to pass another particle is at the time t when the distances are equivalent (assuming the same conditions for motion as in this problem). It is afterwards from this time that one particle will be "passed" the other.

Thanks much for the input :approve:
 

What is 1-dimensional motion in physics?

1-dimensional motion in physics refers to the movement of an object in a straight line, in which its position can be described by a single coordinate along that line. This is also known as linear motion.

What are the basic concepts of 1-dimensional motion?

The basic concepts of 1-dimensional motion include displacement, velocity, acceleration, and time. Displacement is the change in position of an object, velocity is the rate of change of displacement, acceleration is the rate of change of velocity, and time is the duration of the motion.

How is 1-dimensional motion represented graphically?

1-dimensional motion can be represented graphically using a position-time graph, where the y-axis represents the position of the object and the x-axis represents time. The slope of the graph represents the velocity of the object, while the area under the graph represents the displacement.

What is the difference between speed and velocity in 1-dimensional motion?

Speed is the rate at which an object is moving, while velocity is the rate at which an object is changing its position. Velocity takes into account the direction of the object's motion, while speed does not.

What is the formula for calculating acceleration in 1-dimensional motion?

The formula for calculating acceleration in 1-dimensional motion is a = (vf - vi)/t, where a is acceleration, vf is final velocity, vi is initial velocity, and t is time. This formula can also be written as a = Δv/Δt, where Δv is the change in velocity and Δt is the change in time.

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