Question

12

Answer 1

The average accelerations of the five vehicles:

1. Car A: 0 kilometers per square hour.
2. Car B: - 7200 kilometers per square hour.
3. Car C: - 10800 kilometers per square hour.
4. Car D: 0 kilometers per square hour.
5. Car E: 3600 kilometers per square hour.

How to determine the average acceleration of vehicles

Dimensionally speaking, acceleration is velocity (v), in kilometers per hour, divided by time (t), in hours. The average acceleration ($\bar {a}$), in kilometers per square hour, is equal to the difference between the starting and ending velocities ($v_{o}$, $v_{f}$) divided by time ($\Delta t$):

$\bar {a} = \frac{v_{f}-v_{o}}{\Delta t}$      (1)

Now we proceed to calculate the average accelerations of the different cars:

Car A

$\bar {a} = \frac{30\,\frac{km}{h} - 30 \,\frac{km}{h} }{\frac{10}{3600}\,h }$

$\bar {a} = 0\,\frac{km}{h^{2}}$

Car B

$\bar {a} = \frac{20\,\frac{km}{h}-0\,\frac{km}{h}}{\frac{10}{3600}\,h }$

$\bar {a} = 7200\,\frac{km}{h^{2}}$

Car C

$\bar {a} = \frac{0 \,\frac{km}{h} - 30\,\frac{km}{h} }{\frac{10}{3600}\,h }$

$\bar {a} = -10800\,\frac{km}{h^{2}}$

Car D

$\bar {a} = \frac{0\,\frac{km}{h} - 0\,\frac{km}{h} }{\frac{10}{3600}\,h }$

$\bar {a} = 0\,\frac{km}{h^{2}}$

Car E

$\bar {a} = \frac{30\,\frac{km}{h}-20\,\frac{km}{h}}{\frac{10}{3600}\,h }$

$\bar{a} = 3600\,\frac{km}{h^{2}}$

Remark

Select the correct locations on the table. The table shows the changes in velocity for several different cars. Each change takes place over a 10-second interval. Which cars are either speeding up or slowing down?

                                              Car A   Car B    Car C    Car D
Starting velocity (km/h)          30          0         30          20

Ending velocity (km/h)            30         20         0           30

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Answer 2

Car B and E are speeding up, while car C is slowing down.

What is Velocity ?

Velocity is the directional speed of a object in motion as an indication of its rate of change in position as observed from a particular frame of reference.

Step-by-step explanation :

Acceleration (a) is the rate of change of velocity with time.

It is calculated by dividing the change in velocity (Δv) with the time taken for the change to occur.

In this question , the time is 10 sec in all cases.

We can divide the velocity in km/h by 3.6 to convert to m/s

In Car A

Δv = 8.33-8.33 = 0m/s

t = 10s

a = 0 m/s² ⇒car is moving with same speed and in the same direction

Car B

Δv = 5.55-0 = 5.55

t = 10

a = 5.55 / 10 = 0.555 m/s² ⇒car is speeding up

Car C

Δv = 0 - 8.33 = -8.33 m/s

t = 10

a = - 8.33/10 = -0.833 m/s² ⇒car is slowing down

Car D

Δv = 0-0 = 0

t = 10s

a = 0/10 = 0 m/s² ⇒car is at rest

Car E

Δv = 8.33 - 5.55 = 2.78

t = 10

a = 2.78/10 = 0.278 m/s²⇒car is speeding up

Learn More about acceleration here ;

brainly.com/question/13154163

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