Engineering Mechanics: car speeding up

In summary, the car starts from rest, picks up at a uniform rate, and passes three electric posts spaced 360 m apart along a straight road. It takes 10 seconds to travel from the first post to the second post and 6 seconds to go from the second post to the third post. Using the equations $d=\dfrac{1}{2}at^2$, $d+360=\dfrac{1}{2}a(t+10)^2$, and $d+720=\dfrac{1}{2}a(t+16)^2$, the distance from the starting point to the first post can be determined by solving the system for $d$.
  • #1
Joe_1234
25
0
A car starting from rest picks up at a uniform rate and passes three electric post in succession. The post are spaced 360 m apart along a straight rod. The car takes 10 seconds to travel from the first post to the 2nd post and tales 6 seconds to go from the 2nd post to the 3rd post. Determine the distance from the starting point to the first post.
 
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  • #2
let $d$ be the distance from the starting point to the first post, $t$ be the time it takes to reach the first post from rest, and $a$ be the magnitude of the uniform acceleration.

$d = \dfrac{1}{2}at^2$

$d+360 = \dfrac{1}{2}a(t+10)^2$

$d+720 = \dfrac{1}{2}a(t+16)^2$

solve the system for $d$
 
  • #3
skeeter said:
let $d$ be the distance from the starting point to the first post, $t$ be the time it takes to reach the first post from rest, and $a$ be the magnitude of the uniform acceleration.

$d = \dfrac{1}{2}at^2$

$d+360 = \dfrac{1}{2}a(t+10)^2$

$d+720 = \dfrac{1}{2}a(t+16)^2$

solve the system for $d$
Thank you
 

Related to Engineering Mechanics: car speeding up

1. How does the engine of a car help it to speed up?

The engine of a car converts fuel into energy through combustion, which creates the force that moves the car forward. The more fuel that is burned, the more energy is produced, allowing the car to speed up.

2. What role does friction play in a car speeding up?

Friction is the force that opposes motion between two surfaces in contact. In a car, friction between the tires and the road helps to create traction, allowing the car to accelerate and maintain control.

3. How does the weight of a car affect its acceleration?

The weight of a car affects its acceleration by increasing the amount of force needed to overcome its inertia. A heavier car will require more energy to accelerate compared to a lighter car.

4. What is the difference between acceleration and velocity?

Acceleration is the rate at which an object's velocity changes over time, while velocity is the speed and direction of an object's motion. In the context of a car speeding up, acceleration refers to the increase in the car's velocity over time.

5. How do different types of terrain affect a car's acceleration?

The type of terrain a car is driving on can affect its acceleration due to variations in friction. For example, a car may accelerate faster on a smooth, paved road compared to a rough, gravel road due to differences in the amount of friction between the tires and the road surface.

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