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A driver of a car travelling at 52 km h⁻¹ applies the bra... - Science
A driver of a car travelling at 52 km h⁻¹ applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5 s. Another driver going at 3 km h⁻¹ in another car applies his brakes slowly and stops in 10 s. On the same graph paper, plot the speed versus time graphs for the two cars. Which of the two cars travelled farther after the brakes were applied?
Calculations:
For the first car:
Initial speed (
u) =52 \text{ km/h} = 14.4 \text{ m/s}Time (
t) =5 \text{ s}Distance = Area under graph =
\frac{1}{2} \times 14.4 \times 5 = \mathbf{36 \text{ m}}
For the second car:
Initial speed (
u) =3 \text{ km/h} = 0.83 \text{ m/s}Time (
t) =10 \text{ s}Distance = Area under graph =
\frac{1}{2} \times 0.83 \times 10 = \mathbf{4.15 \text{ m}}
Result: The first car travelled farther after the brakes were applied.