Question

Mike is assigned to find the speed of the current of the Lima River. He tosses a leaf into the river. The leaf takes 9 seconds to pass under a bridge 33 feet wide. Find the speed of the current in miles per hour. (5280 feet = 1 mile)

Answer 1

Answer:

160

Step-by-step explanation:

5280 divide by 33=160

Answer 2

The speed of the current will be 2.5 miles/hour

Give:

Width of the bridge = 33 feet

Time taken = 9 seconds

To Find:

The speed of the current in miles per hour

Solution:

We can easily find the speed as given below,

We need the time taken in miles, so convert the width in feet into miles as follows,

5280 feet = 1 miles

Therefore,

1 feet = $\frac{1}{5280}$ miles

Hence,

33 feet = $\frac{1}{5280}$ × 33

= 0.00625 miles

We need the time taken in hours, so convert the time in seconds into hours as follows,

3600 seconds = 1 hours

Therefore,

1 second = $\frac{1}{3600}$ hour

Hence,

9 seconds = $\frac{1}{3600}$ × 9 hour

= 0.0025 hour

Speed of a body = $\frac{Distance travelled}{Time taken}$

We have distance travelled = 0.00625 miles

Time taken = 0.0025 hours

Hence,

The speed of the current = $\frac{0.00625}{0.0025}$

= 2.5 miles/hours

Hence, the speed of the current is 2.5 miles/hours

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