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2 years ago

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You work for the police. An accident has happened. A farmer was taking his dairy cows for milking across a road. The crossing po

int was 100m from a blind bend. In normal conditions with an alert driver obeying the speed limit of 30m/s a car can safely stop before reaching the crossing point. Mr Hoyland was driving home, saw the cows around the bend and was unable to stop. He ran into one of the cows and killed it.

1 answer:

ikadub [295]2 years ago

8 0

Answer:

Since the stopping distance is less than the thinking distance, Mr Hoyland is therefore responsible for the accident

Explanation:

. In normal road conditions and with an alert and sober driver the car

could have stopped before the crash.

2. The reaction time of an alert and sober driver is 0.6s.

3. The reaction time of a drunk driver could be 2s.

4. The initial speed of the car was 30m/s

5. From the time of applying the brakes the total braking distance in

normal conditions is 70m

6. From the time of applying the brakes the total braking distance in bad

conditions is 90m

7. From the time of applying the brakes in normal conditions the car would

reach 15m/s in 52m

You are a forensic expert working for the police. You must analyse the facts and produce a

report stating whether or not Mr Hoyland was responsible for the accident.

1. Calculate the thinking distance for a car travelling at 30m/s

2. Calculate the braking distance for a car travelling in normal conditions at 30m/s

3. Calculate the total stopping distance.

4. REMEMBER TO SHOW YOUR WORKING OUT

Challenge:

1. Is Mr Hoyland responsible for the accident?

2. Explain your answer giving CLEAR reasons for your answer and likely causes.

The Thinking distance = 100m

The breaking distance = 70m

A breaking distance = Stopping distance = 70m

Since the stopping distance is less than the thinking distance, Mr Hoyland is therefore responsible for the accident

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2 years ago

The perihelion of the comet TOTAS is 1.69 AU and the aphelion is 4.40 AU. Given that its speed at perihelion is 28 km/s, what is

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Answer:

The speed at the aphelion is 10.75 km/s.

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The angular momentum is defined as:

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$t = \frac{\Delta L}{\Delta t}$

$t \Delta t = \Delta L$

$\Delta L = 0$

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$L_{a} = L_{p}$ (2)

Replacing equation 1 in equation 2 it is gotten:

$mr_{a}v_{a} =mr_{p}v_{p}$ (3)

Where m is the mass of the comet, $r_{a}$ is the orbital radius at the aphelion, $v_{a}$ is the speed at the aphelion, $r_{p}$ is the orbital radius at the perihelion and $v_{p}$ is the speed at the perihelion.

From equation 3 v_{a} will be isolated:

$v_{a} = \frac{mr_{p}v_{p}}{mr_{a}}$

$v_{a} = \frac{r_{p}v_{p}}{r_{a}}$ (4)

Before replacing all the values in equation 4 it is necessary to express the orbital radius for the perihelion and the aphelion from AU (astronomical units) to meters, and then from meters to kilometers:

$r_{p} = 1.69 AU x \frac{1.496x10^{11} m}{1 AU}$ ⇒ $2.528x10^{11} m$

$r_{p} = 2.528x10^{11} m x \frac{1km}{1000m}$ ⇒ $252800000 km$

$r_{a} = 4.40 AU x \frac{1.496x10^{11} m}{1 AU}$ ⇒ $6.582x10^{11} m$

$r_{p} = 6.582x10^{11} m x \frac{1km}{1000m}$ ⇒ $658200000 km$

Then, finally equation 4 can be used:

$v_{a} = \frac{(252800000 km)(28 km/s)}{(658200000 km)}$

$v_{a} = 10.75 km/s$

Hence, the speed at the aphelion is 10.75 km/s.

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