Applied mechanics?
2017-09-27 11:42 pm
A car is travelling at 12 m/s for a period of 10 s, before accelerating at a rate of 4 m/s² for 5 s. After acceleration, the car travels at a constant velocity for 8 s. Determine the total displacement
回答 (2)
2017-09-27 11:55 pm
Divide the journey into 3 parts.
Part 1 : travelling at 12 m/s for 10 s
Displacement = (12 m/s) × (10 s) = 120 m
Part 2 : accelerating at a rate of 4 m/s² for 5 s
s = ut + (1/2)at²
s = (12 m/s) × (5 s) + (1/2) × (4 m/s²) × (5 s)²
Displacement, s = 110 m
v = u + at
v = (12 m/s) + (4 m/s) × (5 s)
Final velocity, v = 32 m/s
Part 3 : travelling at a constant velocity for 8 s
Displacement = (32 m/s) × (8 s) = 256 m
Total displacement = (120 + 110 + 256) m = 486 m
Part 1 : travelling at 12 m/s for 10 s
Displacement = (12 m/s) × (10 s) = 120 m
Part 2 : accelerating at a rate of 4 m/s² for 5 s
s = ut + (1/2)at²
s = (12 m/s) × (5 s) + (1/2) × (4 m/s²) × (5 s)²
Displacement, s = 110 m
v = u + at
v = (12 m/s) + (4 m/s) × (5 s)
Final velocity, v = 32 m/s
Part 3 : travelling at a constant velocity for 8 s
Displacement = (32 m/s) × (8 s) = 256 m
Total displacement = (120 + 110 + 256) m = 486 m
2017-09-27 11:53 pm
v = u + at
v = 12 + 4*5
v = 32 m/s (for the 8 sec)
s1 = 12(10)
s2 = 12(5) + (4/2)(5)^2
s3 = 32(8)
total = s1 + s2 + s3
v = 12 + 4*5
v = 32 m/s (for the 8 sec)
s1 = 12(10)
s2 = 12(5) + (4/2)(5)^2
s3 = 32(8)
total = s1 + s2 + s3
收錄日期: 2021-04-18 17:55:41
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