two cars start together in the same direction from the same places . the first goes at the speed of 10km/hr and the second goes at the speed 8km/hr and increases he speed by 1/2 km each suceeding hours . after how many hours the second car overtake the first car.if both of them go on non stop
Answers
Answered by
1
Due to time constraints only 3/5 question will be answered...
(1)
distance travelled in the first case
d1 = velocity X time = 40 km/hr X (1/12) hr
or
d1 = 3.33 km
distance travelled in second case
d2 = 50 km/hr X (1/6) hr
or
d2 = 8.33 km
distance travelled in third case
d3 = 25 km/hr X (1/4) hr
or
d3 = 6.25 km
so total distance travelled = 3.33 km + 8.33 km + 6.25 km = 17.91 km
and
total time taken = (1/12) hr + (1/6) hr + (1/4) hr = 0.5 hr
thus, the average speed will be
vav = total distance travelled / total time taken = 17.91 km / 0.5 hr
thus,
vav = 35.82 km/hr
(3)
we know that
v2 - u2 = 2as
here
v = 0 m/s (as teh bullet stops eventually)
u = 100 m/s
s = 10 cm = 0.1 m
now, by rearranging the above equation, we will get the retardation
a = (v2 - u2) / 2s = -u2/2s
or
a = -(100)2 / (2X0.1)
thus, the retardation will be
a = - 50000 m/s2
(4)
we know that
s = ut + (1/2)at2
here
u = 0.5 m/s
a = - 0.05 m/s2
and
v2 - u2 = 2as
or in this case
s = -u2 / 2a
or as v = 0, we have
s = - (0.5)2 / -(2X0.05)
or
s = 0.25/0.1
thus, s = 2.5m
now, by substituting the values in the first equation we get
5 = 0.5t - (0.05/2)t2
or
0.025t2 - 0.5t + 2.5 = 0
this is a quadratic equation which can be solved to get the values of t.
so, we get
t =10 seconds
Due to time constraints only 3/5 question will be answered...
(1)
distance travelled in the first case
d1 = velocity X time = 40 km/hr X (1/12) hr
or
d1 = 3.33 km
distance travelled in second case
d2 = 50 km/hr X (1/6) hr
or
d2 = 8.33 km
distance travelled in third case
d3 = 25 km/hr X (1/4) hr
or
d3 = 6.25 km
so total distance travelled = 3.33 km + 8.33 km + 6.25 km = 17.91 km
and
total time taken = (1/12) hr + (1/6) hr + (1/4) hr = 0.5 hr
thus, the average speed will be
vav = total distance travelled / total time taken = 17.91 km / 0.5 hr
thus,
vav = 35.82 km/hr
(3)
we know that
v2 - u2 = 2as
here
v = 0 m/s (as teh bullet stops eventually)
u = 100 m/s
s = 10 cm = 0.1 m
now, by rearranging the above equation, we will get the retardation
a = (v2 - u2) / 2s = -u2/2s
or
a = -(100)2 / (2X0.1)
thus, the retardation will be
a = - 50000 m/s2
(4)
we know that
s = ut + (1/2)at2
here
u = 0.5 m/s
a = - 0.05 m/s2
and
v2 - u2 = 2as
or in this case
s = -u2 / 2a
or as v = 0, we have
s = - (0.5)2 / -(2X0.05)
or
s = 0.25/0.1
thus, s = 2.5m
now, by substituting the values in the first equation we get
5 = 0.5t - (0.05/2)t2
or
0.025t2 - 0.5t + 2.5 = 0
this is a quadratic equation which can be solved to get the values of t.
so, we get
t =10 seconds
(1)
distance travelled in the first case
d1 = velocity X time = 40 km/hr X (1/12) hr
or
d1 = 3.33 km
distance travelled in second case
d2 = 50 km/hr X (1/6) hr
or
d2 = 8.33 km
distance travelled in third case
d3 = 25 km/hr X (1/4) hr
or
d3 = 6.25 km
so total distance travelled = 3.33 km + 8.33 km + 6.25 km = 17.91 km
and
total time taken = (1/12) hr + (1/6) hr + (1/4) hr = 0.5 hr
thus, the average speed will be
vav = total distance travelled / total time taken = 17.91 km / 0.5 hr
thus,
vav = 35.82 km/hr
(3)
we know that
v2 - u2 = 2as
here
v = 0 m/s (as teh bullet stops eventually)
u = 100 m/s
s = 10 cm = 0.1 m
now, by rearranging the above equation, we will get the retardation
a = (v2 - u2) / 2s = -u2/2s
or
a = -(100)2 / (2X0.1)
thus, the retardation will be
a = - 50000 m/s2
(4)
we know that
s = ut + (1/2)at2
here
u = 0.5 m/s
a = - 0.05 m/s2
and
v2 - u2 = 2as
or in this case
s = -u2 / 2a
or as v = 0, we have
s = - (0.5)2 / -(2X0.05)
or
s = 0.25/0.1
thus, s = 2.5m
now, by substituting the values in the first equation we get
5 = 0.5t - (0.05/2)t2
or
0.025t2 - 0.5t + 2.5 = 0
this is a quadratic equation which can be solved to get the values of t.
so, we get
t =10 seconds
Due to time constraints only 3/5 question will be answered...
(1)
distance travelled in the first case
d1 = velocity X time = 40 km/hr X (1/12) hr
or
d1 = 3.33 km
distance travelled in second case
d2 = 50 km/hr X (1/6) hr
or
d2 = 8.33 km
distance travelled in third case
d3 = 25 km/hr X (1/4) hr
or
d3 = 6.25 km
so total distance travelled = 3.33 km + 8.33 km + 6.25 km = 17.91 km
and
total time taken = (1/12) hr + (1/6) hr + (1/4) hr = 0.5 hr
thus, the average speed will be
vav = total distance travelled / total time taken = 17.91 km / 0.5 hr
thus,
vav = 35.82 km/hr
(3)
we know that
v2 - u2 = 2as
here
v = 0 m/s (as teh bullet stops eventually)
u = 100 m/s
s = 10 cm = 0.1 m
now, by rearranging the above equation, we will get the retardation
a = (v2 - u2) / 2s = -u2/2s
or
a = -(100)2 / (2X0.1)
thus, the retardation will be
a = - 50000 m/s2
(4)
we know that
s = ut + (1/2)at2
here
u = 0.5 m/s
a = - 0.05 m/s2
and
v2 - u2 = 2as
or in this case
s = -u2 / 2a
or as v = 0, we have
s = - (0.5)2 / -(2X0.05)
or
s = 0.25/0.1
thus, s = 2.5m
now, by substituting the values in the first equation we get
5 = 0.5t - (0.05/2)t2
or
0.025t2 - 0.5t + 2.5 = 0
this is a quadratic equation which can be solved to get the values of t.
so, we get
t =10 seconds
Similar questions