A particle starts from rest and traverses a distance l with uniform acceleration, then moves uniformly over a further distance 2l and finally comes to rest after moving a further distance 3l under uniform retardation. Assuming entire motion to be rectilinear motion the ratio of average speed over the journey to the maximum speed on its ways.
a. 1/5
b. 2/5
c. 3/5
d. 4/5
Answers
Answer:
AB=L,BC=2L,CD=3L
It starts from rest and accelerates and then remains in uniform velocity and then retards, this means the maximum velocity will be at point B and let it be v
The area under velocity time graph is displacement and hence we have three equations corresponding to regions AB,BC and CD
2
vt
1
=2,vt
2
=2L,vt
3
=3L
t
1
+t
2
+t
3
=+
v
2L
+
v
2L
+
v
6L
=
v
10L
and the average velocity
=
totaltime
totaldisplacement
v
ˉ
=
t
1
+t
2
+t
3
6L
=
5
3v
Hence,
v
v
ˉ
=
5
3
Answer:
A particle starts from rest and traverses a distance l with uniform acceleration, then moves uniformly over a further distance 2l and finally comes to rest after moving a further distance 3l under uniform retardation. Assuming entire motion to be rectilinear motion the ratio of average speed over the journey to the maximum speed on its ways.
a. 1/5
b. 2/5
c. 3/5
d. 4/5
Ans I thik c