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3 years ago

Can someone help me with 1-2

Physics

1 answer:

ira [324]3 years ago

4 0

Can't really plot a graph here for question 1.

2a) The car speeds up from A to B. The car travels at a constant speed from B to C. The car slows down to a stop from C to D.

b) From the graph, at 10 seconds, the car is moving at 20 m/s.

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A police officer is parked by the side of the road, when a speeding car travelling at 50 mi/hrpasses. The police car immediately

Blababa [14]

Answer:

a) time taken to catch up with speeding car is 12.25 secs

b) the police car will travel 273.8 m to catch up with the speeding car

Explanation:

Given that;

speed of car $V_{c}$ = 50 mi/hr = 22.352 m/s

acceleration of police car = 10 mi/hr = 4.47 m/s²

$V_{f}$ = 70 mi/hr = 31.29 m/s

Now time taken to reach maximum speed is t₁

$V_{f}$ = $V_{i}$ + at₁

we substitute

31.29 = 0 + 4.47t₁

t₁ = 31.29 / 4.47

t₁ = 7 sec

now

d₁ = 0 + 1/2 × at₁²

d₁ = 0 + 1/2 × 0 + 4.47×(7)²

d₁ = 109.5 m

so distance travelled by the speeding car in time t₁ will be

$d_{c}$ = $V_{c}$ × t₁

we substitute

$d_{c}$ = 22.352 × 7

$d_{c}$ = 156.46 m

now distance between polive car and speeding car

Δd = $d_{c}$ - d₁

Δd = 156.46 - 109.5

Δd = 46.96 m

time taken to cover Δd will be

t₂ = Δd / ( $V_{f}$ - $V_{c}$ )

t₂ = 46.96 / ( 31.29 - 22.352 )

t₂ = 46.96 / 8.938

t₂ = 5.25 sec

distance travelled by the police in time t₂ will be

d₂ = $V_{f}$ × t₂

d₂ = 31.29 × 5.25

d₂ = 164.3 m

a) How long will it take before the officer catches up to the speeding car;

time taken to catch up with speeding car;

t = t₁ + t₂

t = 7 + 5.25

t = 12.25 secs

Therefore, time taken to catch up with speeding car is 12.25 secs

b) how far will it have travelled in order to do so;

distance = d₁ + d₂

distance = 109.5 + 164.3

distance = 273.8 m

Therefore, the police car will travel 273.8 m to catch up with the speeding car

6 0

3 years ago

The boiling point of water at sea level is 100 °c. at higher altitudes, the boiling point of water will be

Scilla [17]

<span> The boiling point of water at sea level is 100 °C. At higher altitudes, the boiling point of water will be.....
a) higher, because the altitude is greater.
b) lower, because temperatures are lower.
c) the same, because water always boils at 100 °C.
d) higher, because there are fewer water molecules in the air.
==> e) lower, because the atmospheric pressure is lower.
--------------------------
Water boils at a lower temperature on top of a mountain because there is less air pressure on the molecules.
-------------------
I hope this is helpful. </span>

8 0

3 years ago

An engine is used to lift a beam weighing 9,800 N up to 145 m. How much work must the engine do to lift this beam? How much work

Arturiano [62]

Explanation:

Given that,

Weight of the engine used to lift a beam, W = 9800 N

Distance, d = 145 m

Work done by the engine to lift the beam is given by :

W = F d

$W=9800\ N\times 145\ m\\\\W=1421000\ J\\\\W=1421\ kJ$

Let W' is the work must be done to lift it 290 m. It is given by :

$W'=9800\ N\times 290\ m\\\\W'=2842000\ J\\\\W'=2842\ kJ$

Hence, this is the required solution.

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3 years ago

If the mass of an object increases by a factor 2, kinetic energy?

emmainna [20.7K]

Answer:

A) Increases by a factor of 2

Explanation:

Kinetic energy can be defined as an energy possessed by an object or body due to its motion.

Mathematically, kinetic energy is given by the formula;

$K.E = \frac{1}{2}MV^{2}$

Where;

K.E represents kinetic energy measured in Joules.

M represents mass measured in kilograms.

V represents velocity measured in metres per seconds square.

Given that mass, m = 2m

Substituting into the equation, we have;

K.E = ½mv²

K.E = ½*2mv²

Cross-multiplying, we have;

2K.E = 2mv²

Hence, if the mass of an object increases by a factor 2, kinetic energy is increased by a factor of 2.

5 0

3 years ago

Distinguish between nonsampling error and sampling error. Choose the correct answer below.

kiruha [24]

Answer:

The correct answer is D.

Non-sampling error is the error that results from under-coverage, non-response bias, response bias, or data-entry errors. Sampling error is the error that results because a sample is being used to estimate information about a population.

Explanation:

Sampling error is related to the variation between the true values of the sample and the population. If occurred, it is always random depending upon the sample chosen.

Non-sampling error can be random as well as non-random. Non-sampling error can occur irrespective of the sample chosen. It is related to the inappropriate analysis of the data.

5 0

3 years ago