The power (P) of an engine is measured in horsepower using the formula:
$$
P = \frac{R \times T}{5252}
$$
where R is the engine speed measured in revolutions per minute (RPM) and T is the torque measured in appropriate units - Leaving Cert Mathematics - Question 8 - 2019
Question 8
The power (P) of an engine is measured in horsepower using the formula:
$$
P = \frac{R \times T}{5252}
$$
where R is the engine speed measured in revolutions per m... show full transcript
Worked Solution & Example Answer:The power (P) of an engine is measured in horsepower using the formula:
$$
P = \frac{R \times T}{5252}
$$
where R is the engine speed measured in revolutions per minute (RPM) and T is the torque measured in appropriate units - Leaving Cert Mathematics - Question 8 - 2019
Step 1
Find the power of an engine that generates 480 units of torque at 2500 RPM. Give your answer correct to the nearest whole number.
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Answer
To find the power, we substitute the values into the formula:
P=5252480×2500
Calculating this gives:
P=52521200000≈228.48
Rounding to the nearest whole number, the power is 228 horsepower.
Step 2
Rearrange the formula to write R in terms of P and T.
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Answer
Starting with the original formula:
P=5252R×T
We rearrange it to solve for R:
R=TP×5252
Step 3
Complete the table below to show the company's loss/profit for each of the first six months of trading.
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Answer
Month
1
2
3
4
5
6
Profit (€)
-4000
-3750
-3500
-3250
-3000
-2750
Step 4
Show that the profit the company makes in month n is given by the formula Tn = 250n - 4250.
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Answer
The profit for month n can be calculated as follows:
Initial loss of €4000 reduces by €250 each month, so:
Tn=−4000+(n−1)250
Simplifying gives:
Tn=250n−4250
Step 5
What profit does the company make in January 2018 (i.e. month 25)?
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Answer
To find the profit in month 25, substitute n = 25 into the formula:
T25=250(25)−4250
Calculating this gives:
T25=6250−4250=2000
Thus, the company makes a profit of €2000 in January 2018.
Step 6
Find the month in which the company breaks even (i.e. €0 profit).
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Answer
Setting the profit formula to zero:
0=250n−4250
Solving for n gives:
250n=4250⇒n=17
Thus, the company breaks even in month 17.
Step 7
Find Sn, the general term for the total profit of the company after n months.
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Answer
The total profit after n months can be found by summing the profit for each month:
Sn=k=1∑nTk=k=1∑n(250k−4250)
This simplifies to:
Sn=250(2n(n+1))−4250n=2250n(n+1)−4250n
Step 8
Hence, find the total profit of the company at the end of January 2019 (i.e. month 37).
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