Starting from a stationary position a bus attains a velocity of 6m/s in 30s .Then the driver of the bus applies a brake such that the velocity of the bus comes down to 4m/s in the next 5s .Cal culate the arceleration of the bus in both cases.
Answers
• Acceleration in 1st Case 0.2m/s².
• Acceleration in 2nd Case 0.4m/s².
Explanation:
Solution:-
Firstly we calculate the acceleration in 1st condition.
- Initial velocity ,u = 0m/s
- Final velocity ,v = 6m/s
- Time taken ,t = 30 s
we have to calculate the acceleration of the bus . As we know that acceleration is defined as the rate of change of velocity at per unit.
• a = v-u/t
where,
v is the final velocity
a is the acceleration
u is the initial velocity
t is the time taken
Substitute the value we get
→ a = 6-0/30
→ a = 6/30
→ a = 1/5
→ a = 0.2 m/s²
- Hence, the acceleration of bus in 1st case is 0.2m/s².
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Now, we have to calculate the acceleration of bus in 2nd case.
- Final velocity ,v = 4m/s
- Initial velocity ,u = 6m/s
- Time taken ,t = 5
Substitute the value we get
→ a = v-u/t
→ a = 4-6/5
→ a = -2/5
→ a = -0.4m/s²
Here Negative sign show retardation
- Hence, the acceleration of the bus in 2nd case is 0.4m/s².
Answer:
in first case,
initial velocity "u" = 0 m/s
final velocity "v"= 6m/s
time = 30 s
acceleration = final velocity- initial velocity/time
= 6-0/30
= 6/30
= 0.2 m/s²
in second case,
initial velocity "u" = 6m/s
final velocity "v" = 4m/s
time = 5 s
acceleration = final velocity - initial velocity/ time
= 4-6/5
= -2/5
= - 0.4m/s²