Time taken (tt) = 15 minutes = 15 × 60 seconds = 900 seconds
Speed (vv) = 2 m/s
Formula:
Distance (dd) = Speed × Time
d=v×td=v×t
Calculation:
d=2 m/s×900 s=1800 md=2m/s×900s=1800m
Answer: The distance between Geetha’s house and the school is 1800 meters (1.8 km).
Q- A car starts from rest and it is travelling with a velocity of 20 m/s in 10 s. What is its acceleration?
Given:
Initial velocity (uu) = 0 m/s
Final velocity (vv) = 20 m/s
Time (tt) = 10 seconds
Formula:
Acceleration (aa) = ΔvttΔv
ΔvΔv = v−uv−u
Calculation:
Δv=20 m/s−0 m/s=20 m/sΔv=20m/s−0m/s=20m/s
a=20 m/s10 s=2 m/s2a=10s20m/s=2m/s2
Answer: The acceleration of the car is 2 m/s².
Q- A bus can accelerate with an acceleration of 1 m/s². Find the minimum time for the bus to attain the speed of 100 km/h from 50 km/h.
Given:
Initial speed (uu) = 50 km/h = 50×10003600360050×1000 m/s = 500003600360050000 m/s ≈ 13.89 m/s
Final speed (vv) = 100 km/h = 100×100036003600100×1000 m/s = 10000036003600100000 m/s ≈ 27.78 m/s
Acceleration (aa) = 1 m/s²
Formula:
Time (tt) = ΔvaaΔv
Δv=v−uΔv=v−u
Calculation:
Δv=27.78 m/s−13.89 m/s=13.89 m/sΔv=27.78m/s−13.89m/s=13.89m/s
t=13.89 m/s1 m/s2=13.89 st=1m/s213.89m/s=13.89s
Answer: The minimum time for the bus to attain the speed of 100 km/h from 50 km/h is approximately 13.89 seconds.
