Physics, 20.09.2020 15:01, Tbutler21

A red toy car has an acceleration of 4.00 m/s², whereas a blue toy car has an acceleration of 2.00 m/s². You start the blue car from rest down a track of length 9.00 m. How much time must you wait before starting the red car from rest, such that the two cars reach the end of the track at the same time?

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answered: janetcooly

One must wait 0.88 secs before starting the red car

Explanation:

To calculate how much time to wait before starting the red car from rest, we will calculate the time it will take the blue car to reach the end of the track from rest and the time it will take the red car to reach the end of the track from rest; then, the difference between these times is the time one must wait before starting the red car from rest such that two cars reach the end of the track at the same time

For the red car,

Acceleration = 4.00 m/s²

Initial velocity = 0 m/s (Since it is starting from rest)

Distance = 9.00 m

Let the time spent by the red car be $t_{r}$

From one of the equations of kinematics for linear motion

$S = ut + \frac{1}{2}at^{2}$

Where

is the distance traveled

is the initial velocity

is the time

and is the acceleration

Then, for the red car

$9.00 = (0)(t_{r}) + \frac{1}{2}(4.00)(t_{r})^{2}$

$9.00 = (2.00)(t_{r})^{2}$

$t_{r} = \sqrt{\frac{9.00}{2.00} }$

$t_{r} =2.12 secs$

This is the time it will take the red car to reach the end of the track

For the blue car

Acceleration = 2.00 m/s²

Initial velocity = 0 m/s (Since it is starting from rest)

Distance = 9.00 m

Let the time spent by the red car be $t_{b}$

Also from

$S = ut + \frac{1}{2}at^{2}$

$9.00 = (0)(t_{r}) + \frac{1}{2}(2.00)(t_{b})^{2}$

$9.00 = (t_{b})^{2}$

$t_{b} = \sqrt{9}$

$t_{b} = 3secs$

This is the time it will take the blue car to reach the end of the track

The difference of the times is

$t_{b} - t_{r}$ = 3 secs - 2.12 secs

= 0.88 secs

Hence, one must wait 0.88 secs before starting the red car

answered: Guest

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

answered: Guest

myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.

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A red toy car has an acceleration of 4.00 m/s², whereas a blue toy car has an acceleration of 2.00 m...