Civil Engineering - Applied Mechanics - Discussion
Discussion Forum : Applied Mechanics - Section 1 (Q.No. 4)
4.
The equation of motion of a particle starting from rest along a straight line is x = t3 - 3t2 + 5. The ratio of the accelerations after 5 sec and 3 sec will be
Discussion:
14 comments Page 2 of 2.
Priyanka marmat said:
1 decade ago
d"x/dt = 6t-6.
6(5)-6 = 24.
6(4)-6 = 12.
24/12 = 2.
The ratio is 2.
6(5)-6 = 24.
6(4)-6 = 12.
24/12 = 2.
The ratio is 2.
Dawit tamiru said:
1 decade ago
Another method d"x/dt = 6t-6.
6(5)-6 = 24 and 6(3)-6 = 12. we got the ratio 2.
6(5)-6 = 24 and 6(3)-6 = 12. we got the ratio 2.
Jadecliff said:
1 decade ago
x = Distance.
v = Velocity = dx/dt.
a = Acceleration = dv/dt.
From x = t3 - 3t2 + 5.
v = 3t2 - 6t.
a = 6t - 6.
By substituting 5 sec and 3 sec in a.
a1 = 24.
a2 = 12.
a1 : a2 = 2 : 1.
v = Velocity = dx/dt.
a = Acceleration = dv/dt.
From x = t3 - 3t2 + 5.
v = 3t2 - 6t.
a = 6t - 6.
By substituting 5 sec and 3 sec in a.
a1 = 24.
a2 = 12.
a1 : a2 = 2 : 1.
(1)
Saurabh said:
1 decade ago
x = t3 - 3t2 + 5.
dx/dt = t2/2 - 3t.
= 12.5 - 15.
= -2.5.
4.5 - 9.
= -4.5.
4.5/2.5 = 1.8 = 2.
dx/dt = t2/2 - 3t.
= 12.5 - 15.
= -2.5.
4.5 - 9.
= -4.5.
4.5/2.5 = 1.8 = 2.
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