17. A bicycle moves with a constant velocity of 5 km/h
for 10 minutes and then decelerates at the rate
1 km/h”, till it stops. Find the total distance covered
by the bicycle.
Answers
Answer:
Total distance covered by the car
= 13.3 km
Step by step explanations :
Given that,
A bicycle moves with a constant velocity of 5 km/h
for 10 minutes
here,
Initial velocity of the bicycle = 5 km/h
time taken = 10 miniutes
= 10/60 h
= 1/6 h
We know that
in a constant velocity acceleration is 0
so,
S = ut + ½ at²
S = 5(1/6)
S = 5/6 km
now
brakes are applied
so final velocity = 0 m/s
given acceleration = -1 km/h²
now we have,
Initial velocity(u) = 5 km/h
final velocity(v) = 0 km/h
acceleration(a) = -1 km/h
v² = u² + 2as
(0)² = 5² + 2(-1)s
-2s = -25
S = 25/2
now total distance covered by the bicycle
= 5/6 + 25/2
(10 + 150)/12
= 160/12
= 13.3 km
so,
Total distance covered by the car
= 13.3 km
• Initial velocity (u) = 5 km/hr
• time = 10 min
=> 10/60
=> 0.16667 hrs.
• Acceleration (a) = 0 m/s²
(Because velocity is constant)
___________ [ GIVEN ]
• We have to find the total distance (S). Before that we have to find the distance (s1).
____________________________
We know that..
» s = ut + 1/2 at²
Put the known values in above formula
→ s = 5(0.16667) + 1/2 (0)(0.16667)²
→ s = 0.83335 + 0
→ s1 = 0.83335
______________________________
Now..
After applying brakes.
• Initial velocity (u) = 5 km/hr
• Final velocity (v) = 0 km/hr
• Acceleration (a) = - 1 km/hr
____________ [ GIVEN ]
• We have to find the distance (s2).
_____________________________
We know that..
» v² - u² = 2as
Put the known values in above formula
→ (0)² - (5)² = 2(-1)(s2)
→ - 25 = - 2s2
→ 2s2 = 25
→ s2 = 25/2
→ s2 = 12.5
_____________________________
Now..
Total distance = s1 + s2
→ 0.83335 + 12.5
→ 13.33335
→ 13.33 km (approx.)
_____________________________
13.33 km is the total distance covered by the bicycle.
________ [ ANSWER ]
_____________________________