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rewona [7]
3 years ago
9

The 2.5-Mg van is traveling with a speed of 100 km>h when the brakes are applied and all four wheels lock. If the speed decre

ases to 40 km>h in 5 s, determine the coefficient of kinetic friction between the tires and the road.
Physics
1 answer:
Andrew [12]3 years ago
4 0

Answer:

0.34

Explanation:

2.5 Mg = 2500 kg

The change in speed from 100 km/h to 40 km/h is

\Delta v = 100 - 40 = 60 km/h = 60 * 1000 / (60 * 60) = 16.67 m/s

The deceleration caused by friction force is the change in speed per unit of time

a = \Delta v / \Delta t = 16.67 / 5 = 3.33 m/s^2

Using Newton 2nd law we can calculate the friction force that caused this deceleration:

F = ma = 2500 * 3.33 = 8333 N

Let g = 9.8m/s2. Friction force is the product of normal (gravity) force and friction coefficient

F = mg\mu

8333 = 2500*9.8\mu

\mu = \frac{8333}{2500 * 9.8} = 0.34

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Alexeev081 [22]

Answer: a=-2.4525 m/s^2

d=s=190.3 m

Explanation:The only force that is stopping the car and causing deceleration is the frictional force Fr

Fr = 25% of weight

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W=17167.5

Hence

Fr=\frac{25}{100} * -17167.5\\\\Fr=-4291.875 N

Frictional force is negative as it acts in opposite direction

According to newton second law of motion

F=ma

hence

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given

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to get t we know that final velocity v=0

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