Saved Bookmarks
| 1. |
A car Moves with a speed of 80/km hr For 15 min and then with a speed of 60/km for next 15 min The total distance covered by the car is? |
|
Answer» Total distance covered = 35 kmExplanation:velocity in first half v₁ = 80 km/HR = m/s= 200/9 m/svelocity in second half v₂ = m/s = 60 X 5/18 = 50/ 3 m/stime = t₁ = t₂ = 15 min = 15 x 60 secDistance covered in first half s₁ = v₁t₁ = =20,000 m = 20 kmDistance covered in second half s₂ = v₂t₂ = = 15,000 m = 15 kmTotal distance covered s = s₁ + s₂ = 20 + 15 = 35 kmAlternate Method :Formula used : If a body covers first half time (t) with velo v₁ and second half time with velo v₂ thenAverage velo = (v₁ + v₂)/2∴ Avg velo v = = 70 km/hrTotal time t = 30 min = 30/60 hr = 0.5 hrTotal dist covered s = vt = 70 x 0.5 = 35 km |
|