2. A motorcycle starting from rest accelerates uniformly to 20m/s in 10s.
(a) Find the acceleration of the motorcycle.
(b) If the motorcycle kept moving with uniform acceleration calculated in a), how much longer would it take for the motor cycle to attain a velocity of 50m/s.
A question
2007-09-21 1:55 am
回答 (2)
2007-09-21 2:01 am
✔ 最佳答案
(a) a = (v – u) / t
Therefore acceleration
= (20 – 0) / 10
= 2 ms-2
(b)
Apply a = (v – u) / t again,
2 = (50 – 20) / t
t = 30/2
t = 15 s
Therefore the motorcycle would take 15 more seconds (taken from the velocity of 20 m/s) to attain the velocity of 50m/s
2007-09-21 2:03 am
(a)
u=0, v= 20m/s, t =10s
v= u + at
20 = 0 +a(10)
a = 2 m/s²
(b)
v'= 50m/s, u'= v = 20m/s
v'= u' +aT
50 = 20 +2T
T = 15s
It takes 15s longer to attain the velocaity
u=0, v= 20m/s, t =10s
v= u + at
20 = 0 +a(10)
a = 2 m/s²
(b)
v'= 50m/s, u'= v = 20m/s
v'= u' +aT
50 = 20 +2T
T = 15s
It takes 15s longer to attain the velocaity
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