Question

the braking distance of a car moving at a velocity of v1 = 20m/s is equal to 40m. What will the braking distance S2 be at velocity of v2=25 m/s if it undergoes the same acceleration in both cases?
75.5
70
62.5
44.5
55
решение

Answer 1

Ответ:

Data:

S_1 = 40 m

V_1 = 20 m/s

V_2 = 25 m/s

V_x = 0 m/s

To Find:

a, S_2

Answer:

S = (V²_x - V²_0)/2a

a = (V²_x - V²_1)/2S_1 = (0 - 20²)/2*40 = -400/80 = -5 m/s²

S_2 = (0 - 25²)/2*(-5) = -625/-10 = 62,5 m

Answer 2

Ответ:

62.5

Объяснение:

V₁ = 20 m/s

S₁ = 40m

V₂ = 25 m/s

V = 0

S₂ = ?

S = (V²-V²₀)/2a

S₁ = -V₁²/2a

S₂ = -V₂²/2a

S₂/S₁ = (V₂/V₁)²

S₂ = S₁* (V₂/V₁)² = 40 m*(25 m/s / 20 m/s)² = 62.5 m