Equations: Speed=Distance/Time.
Distance is on the top and the Time is in the bottom in the equation
Use the equation above to answer the following questions. Show your work and include the units
1. A football field is about 100m long. It it takes a person 20 second to run its length, How fast (What speed) were they running?
2. The pitcher's mound in baseball is 85m from the plate. It take 4 second for a pitch to reach the plate. How fast is the pitch?
3. If you drive at 100km/hr for 6 hours, How far will you go?
4. If you run at 12m/s for 15 minutes, How far will you go?
5. Every summer I drive to Pennsylvania. It takes 895km to get there. If I average 100km/hr, How much time will I spend driving?
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Answer:
Explanation:
They are exercises of uniform rectilinear movement.
The formula for uniform motion is V = d/t
where
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===> Exercise 1
1. A football field is about 100m long. It it takes a person 20 second to run its length, How fast (What speed) were they running?
Data:
Knowing that the formula is V =d/t, we do not clear since we want to calculate the Velocity. We substitute data and solve, then
V = d/t
V = 100 m/20 s
V = 5 m/s
Answer: They were running in the field, at a speed of 5 m/s.
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===> Exercise 2
The pitcher's mound in baseball is 85m from the plate. It take 4 second for a pitch to reach the plate. How fast is the pitch?
Data:
Also in this exercise, we solve it to the previous one, the formula is V = d/t, we do not solve it, because we will calculate the speed, then
V = d/t
V = 85 m/4 s
V = 21.25 m/s
Answer: The velocity of the launch is 21.25 m/s.
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===> Exercise 3
If you drive at 100km/hr for 6 hours, How far will you go?
Data:
The formula for uniform motion is V = d/t.
We solve for the distance d:
d = V * t
d = 100 km/h * 6 h
d = 600 km
Answer: If you drive at a speed of 100 km/h, for 6 hours, you will cover a distance of 600 km.
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===> Exercise 4
If you run at 12 m/s for 15 minutes, How far will you go?
Data:
We calculate time in minutes, so we convert from minutes to seconds.
Knowing that 60 seconds is equal to 1 minute.
t = 15 min * 60 s/1 min = 900 s
The formula for uniform motion is V = d/t.
We solve for the distance d:
d = V * t
d = 12 m/s * 900 s
d = 10800 m = 10.8 Km
Answer: If you run at a speed of 12 m/s in 15 minutes, you will cover a distance of 10800 meters.
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===> Exercise 5
Every summer I drive to Pennsylvania. It takes 895 km to get there. If I average 100 km/hr, How much time will I spend driving?
Data:
The formula for uniform motion is V = d/t.
We clear for time t:
t = d/v
t = 895 km/100 km/h
t = 8.95 h
Answer: You will spend driving a time of 8.95 hours.