High School

A farmer operates a tractor on a farm to fertilize crops. The digital dashboard reads 6.5 miles per hour, with a range of 31 and 1700 rpm.

Chart showing speed and area rate of coverage (acres per hour):
- 3 mph: 5.96 acres/hour
- 3.5 mph: 6.95 acres/hour
- 4 mph: 7.95 acres/hour
- 4.5 mph: 8.94 acres/hour
- 5 mph: 9.94 acres/hour
- 5.5 mph: 10.93 acres/hour
- 6 mph: 11.92 acres/hour
- 6.5 mph: 12.92 acres/hour
- 7 mph: 13.91 acres/hour
- 7.5 mph: 14.90 acres/hour
- 8 mph: 15.90 acres/hour
- 8.5 mph: 16.89 acres/hour
- 9 mph: 17.88 acres/hour
- 9.5 mph: 18.88 acres/hour
- 10 mph: 19.87 acres/hour

Chart showing engine speed and flow rate (gallons per minute):
- 500 rpm: 1 gpm
- 750 rpm: 2.5 gpm
- 1,000 rpm: 4 gpm
- 1,250 rpm: 5.5 gpm
- 1,500 rpm: 7 gpm
- 1,750 rpm: 8.5 gpm
- 2,000 rpm: 10 gpm
- 2,250 rpm: 11.5 gpm
- 2,500 rpm: 13 gpm
- 2,750 rpm: 14.5 gpm

Question: Shifting into first gear generally increases the engine speed (rpm) while decreasing the tractor speed (mph). What would be the effect of this change?

A. Both area rate and flow rate would increase
B. Area rate would increase, and flow rate would decrease
C. Area rate would decrease, and flow rate would increase
D. Both area rate and flow rate would decrease

Answer :

Shifting into first gear increases engine rpm and decreases tractor speed, which leads to a decrease in area rate of coverage and an increase in flow rate. The correct answer is C 'Area rate would decrease, and flow rate would increase.'

When shifting into first gear, the engine speed (rpm) increases while the tractor speed (mph) decreases. According to the provided charts, at a lower tractor speed, the area rate of coverage decreases since the tractor is covering less ground per hour. However, as the engine's rpm increases, the flow rate goes up since more fluid is being pumped through the system per minute.

Given the digital dashboard reading of 6.5 mph and 1700 rpm, if the tractor shifts into first gear and thus decreases speed but increases rpm, we can expect the area rate to decrease because the tractor is moving more slowly. From the chart, if the speed were to decrease from 6.5 mph to a lower speed, the acres covered per hour would also decrease. At the same time, if the rpms were to increase from 1700 rpm, the flow rate would increase because the engine is running faster, moving more fluid as per the flow rate chart.

The correct answer to the question is C: Area rate would decrease, and flow rate would increase.