At a drag race, a jet car travels 1/4 mile in 5.2 seconds. What is the final speed of the
1 answer:
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Answer:
-40 kJ
80 kJ
Explanation:
Work is equal to the area under the pressure vs volume graph.
W = ∫ᵥ₁ᵛ² P dV
2.27) Pressure and volume are linearly related. When we graph P vs V, the area under the line is a trapezoid. So the work is:
W = ½ (P₁ + P₂) (V₂ − V₁)
W = ½ (100 kPa + 300 kPa) (0.1 m³ − 0.3 m³)
W = -40 kJ
2.29) Pressure and volume are inversely proportional:
pV = k
The initial pressure and volume are 500 kPa and 0.1 m³. So the constant is:
(500) (0.1) = k
k = 50
The final pressure is 100 kPa. So the final volume is:
(100) V = 50
V = 0.5
The work is therefore:
W = ∫ᵥ₁ᵛ² P dV
W = ∫₀₁⁰⁵ (50/V) dV
W = 50 ln(V) |₀₁⁰⁵
W = 50 (ln 0.5 − ln 0.1)
W ≈ 80 kJ
Answer
given,
Mass of Kara's car = 1300 Kg
moving with speed = 11 m/s
time taken to stop = 0.14 s
final velocity = 0 m/s
distance between Lisa ford and Kara's car = 30 m
a) change in momentum of Kara's car
Δ P = m Δ v
Δ P = - 1.43 x 10⁴ kg.m/s
b) impulse is equal to change in momentum of the car
I = - 1.43 x 10⁴ kg.m/s
c) magnitude of force experienced by Kara
I = F x t
I is impulse acting on the car
t is time
- 1.43 x 10⁴= F x 0.14
F = -1.021 x 10⁵ N
negative sign represents the direction of force