Question #17497

a football coach starts at the 35 yard-line and walks to the 15-yard line. He turns around and walks to the 40-yard line. He turns around again and walks back to the 0-yard line. He turns around one more and walks back to the 25-yard line thus completing his 10 min of pacing. The coachs average speed is

Expert's answer

1. A football coach starts at the 35-yard line and walks to the 15-yard line.

So, the first part of his displacement is

D1 = 35 - 15 = 20 yards.

2. He turns around and walks to the 40-yard line.

Coach starts from the 15-yard line and walks to the 40-yard line, so his displacement is

D2 = 40 - 15 = 25 yards.

3. He turns around again and walks back to the 0-yard line.

Coach starts from the 40-yard line and walks to the 0-yard line, so his displacement is

D3 = 40 - 0 = 40 yards.

4. He turns around one more and walks back to the 25-yard line.

Coach starts from the 0-yard line and walks to the 25-yard line, so his displacement is

D4 = 0 + 25 = 25 yards.

The total distance walked is

D = D1 + D2 + D3 + D4 = 20 + 25 + 40 + 25 = 110 yards.

So, the coach's average speed is

S = 110[yards]/10[min] = 11 [yards/min].

So, the first part of his displacement is

D1 = 35 - 15 = 20 yards.

2. He turns around and walks to the 40-yard line.

Coach starts from the 15-yard line and walks to the 40-yard line, so his displacement is

D2 = 40 - 15 = 25 yards.

3. He turns around again and walks back to the 0-yard line.

Coach starts from the 40-yard line and walks to the 0-yard line, so his displacement is

D3 = 40 - 0 = 40 yards.

4. He turns around one more and walks back to the 25-yard line.

Coach starts from the 0-yard line and walks to the 25-yard line, so his displacement is

D4 = 0 + 25 = 25 yards.

The total distance walked is

D = D1 + D2 + D3 + D4 = 20 + 25 + 40 + 25 = 110 yards.

So, the coach's average speed is

S = 110[yards]/10[min] = 11 [yards/min].

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