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Question: A train starting from rest and move with a uniform acceleration of 0.2 metre per second sq. for 5 minutes. Calculate the speed acquired and the distance travelled in this time.
Provided that:
- Acceleration = 0.2 m/s sq.
- Time = 5 minutes
- Initial velocity = 0 m/s
Don't be confused! Initial velocity cames as zero because the train starts from rest.
To calculate:
- Final velocity
- Distance travelled
Solution:
- Final velocity = 60 m/s
- Distance travelled = 9000 m
Knowledge required:
- SI unit of acceleration = m/s²
- SI unit of distance = m
- SI unit of time = seconds
- SI unit of velocity = m/s
Using concepts:
- Formula to convert min-sec
- First equation of motion
- Third equation of motion
Using formulas:
• 1 minute = 60 seconds
• 1st eqⁿ of motion → v = u + at
• 3rd eqⁿ of motion → v² - u² = 2as
Where, a denotes acceleration, u denotes initial velocity, v denotes final velocity, s denotes displacement or distance or height, t denotes time taken.
Required solution:
~ Firstly let us convert min-sec!
→ 1 minute = 60 seconds
→ 5 minute = 5 × 60 seconds
→ 5 minute = 300 seconds
- Henceforth, converted!
~ Now by using first equation of motion let us calculate the final velocity!
→ v = u + at
→ v = 0 + (0.2)(300)
→ v = 0 + 60
→ v = 60 m/s
→ Final velocity = 60 m/s
- Henceforth, done!
~ Now by using third equation of motion let us calculate the distance travelled!
→ v² - u² = 2as
→ (60)² - (0)² = 2(0.2)(s)
→ 3600 - 0 = 0.4s
→ 3600 = 0.4s
→ 3600/0.4 = s
→ 36000/4 = s
→ 9000 = s
→ s = 9000 m
→ Distance = 9000 metres
- Henceforth, done!