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A 1000-kg car traveling with a speed of 35 m/s skids to a stop in 25m. Determine the average force applied to the breaks. If it took 3.2s to stop, who much power was generated by the breaks?

User Na
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1 Answer

4 votes

Answer:

1. 24500 N.

2. 191406.25 watt

Step-by-step explanation:

From the question given above, the following data were obtained:

Mass (m) of car = 1000 Kg

Initial velocity (u) = 35 m/s

Distance (s) = 25 m

Final velocity (v) = 0 m/s

Time (t) = 3.2 s

Force (F) =?

Power (P) =?

Next, we shall determine the acceleration of the car. This can be obtained as follow:

Initial velocity (u) = 35 m/s

Distance (s) = 25 m

Final velocity (v) = 0 m/s

Acceleration (a) =?

v² = u² + 2as

0 = 35² + (2 × a × 25)

0 = 1225 + 50a

Collect like terms

0 – 1225 = 50a

– 1225 = 50a

Divide both side by 50

a = – 1225 / 50

a = –24.5 m/s²

1. Determination of the force.

Mass (m) of car = 1000 Kg

Acceleration (a) = –24.5 m/s²

Force (F) =?

F = m × a

F = 1000 × –24.5

F = –24500 N

The negative sign indicate that the force is in opposite direction to the motion of the car.

2. Determination of the power

Force (F) = 24500 N

Distance (s) = 25 m

Time (t) = 3.2 s

Power (P) =?

Next, we shall determine the energy.

Energy = force × distance

Energy = 24500 × 25

Energy = 612500 J

Finally, we shall determine the power. This is illustrated below:

Power = Energy /time

Power = 612500 /3.2

Power = 191406.25 watt

User Karon
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6.4k points