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1 year 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]1 year 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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(b) If the straight-line distance from her home to the university is 10.3 km in a direction 25.0° south of east, what was her av

svet-max [94.6K]

Answer:

The time taken is missing in the question. The time is 18 minutes.

The answer is 34.3 km/hr

Explanation:

Average velocity is the speed or the velocity which is required to cover a distance in a time interval.

The time taken is = 18 min

= 18/60 hours

The distance from the university to her home is = 10.3 km

Therefore, the average velocity is = displacement/time taken

= 10.3 / (18/60) km/hr

= 34.3 km/hr

Hence, the average velocity is 34.3 km/hr

7 0

2 years ago

How long will it take a 2190 W motor to lift a 1.47 x 104 g box, 6.34 x 104 mm vertically.

Rasek [7]

Answer:

t = 4.17 [s]

Explanation:

We know that work is defined as the product of force by distance.

W = F*d

where:

F = force [N] (units of Newtons)

d = distance = 6.34 x 10⁴ [mm] = 63.4 [m]

In order to find the force, we must determine the weight of the box, the weight can be determined by means of the product of mass by gravitational acceleration.

w = m*g

where:

m = mass = 1.47 x 10⁴ [g] = 14.7 [kg]

g = gravity acceleration = 9.81 [m/s²]

w = 14.7*9.81

w = 144.2 [N]

Therefore the work can be calculated.

W = w*d

W = 144.2*63.4

W = 9142.72 [J] (units of Joules)

Power is now defined in physics as the relationship of work at a given time

P = W/t

where:

P = power = 2190 [W]

t = time [s]

Now clearing t, we have.

t = W/P

t = 9142.72/2190

t = 4.17 [s]

6 0

1 year ago

A 6.60-kg block slides with an initial speed of 1.56 m/s up a ramp inclined at an angle of 28.4° with the horizontal. The coeffi

Vlad [161]

Answer:

The distance travel by block before coming to rest is 0.122 m

Explanation:

Given:

Mass of block $m = 6.60$ kg

Initial speed of block $v _{i} = 1.56$ $\frac{m}{s}$

Final speed of block $v_{f} = 0$ $\frac{m}{s}$

Coefficient of kinetic friction $\mu _{k} = 0.62$

Ramp inclined at angle $\theta =$ 28.4°

Using conservation of energy,

Work done by frictional force is equal to change in energy,

$\mu _{k} mgd \cos 28.4 = \Delta K - \Delta U$

Where $\Delta U = mg d\sin 28.4$

$\mu _{k} mgd \cos 28.4 = \frac{1}{2}mv_{i} ^{2} - mgd\sin 28.4$

$\mu _{k} mgd \cos 28.4 +mgd\sin 28.4 = \frac{1}{2}mv_{i} ^{2}$

$d(6.60 \times 9.8 \times 0.62 \times 0.879 + 6.60 \times 9.8 \times 0.475) = \frac{1}{2} \times 6.60 \times (1.56)^{2}$

$d = 0.122$ m

Therefore, the distance travel by block before coming to rest is 0.122 m

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2 years ago

We know that the earth's axis is tilted 23 ½ degrees. On or about June 21 or 22 each year, the summer solstice occurs for those

Dima020 [189]

<span>D) The sun's rays will never be directly overhead. The latitude of 23 ½ degrees north is known as the Tropic of Cancer. Above this imaginary line the sun's rays hit earth with decreased angles.</span>

8 0

2 years ago

Read 2 more answers

During the 440, a runner changes his speed as he comes out of the curve onto the home stretch from 18 ft/sec to 38 ft/sec over a

Sloan [31]

Answer:

$6.67ft/s^2$

Explanation:

We are given that

Initial velocity=u=18ft/s

Final velocity,v=38ft/s

Time=t=3 s

We have to find the average acceleration over that 3 s period.

We know that

Average acceleration,a= $\frac{v-u}{t}{t}$

Using the formula

Average acceleration,a= $\frac{38-18}{3}ft/s^2$

Average acceleration,a= $\frac{20}{3}ft/s^2$

Average acceleration,a= $6.67ft/s^2$

Hence, the average acceleration= $6.67ft/s^2$

5 0

1 year ago