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Issues of Friction

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I'm completely lost - Could you go step by step so I can follow your logic? Thanks.

1. A crate sits on a flatbed truck. This truck, initially travelling at a velocity of 80 km/hour, comes to a stop in 22 meters. What is the minimum coefficient of static friction required between the crate and truck bed, if it is not to slide forward?

2. A hospital traction device is shown in (attached). What is a) the horizontal force and b) the vertical force exerted on the foot by the arrangement, if the cord transmits an undiminished tension T of 5.0 gN?

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Solution Preview

1) Recall that acceleration is the change in velocity over change in time.

Look at the units: v = 80 km/hr = 80,000 m/hr = 22 m/s (initial velocity)

Use the following equation to find the acceleration: v^2 = (vo)^2 + 2a(x-xo), where v^2 is velocity squared, (vo)^2 is initial velocity squared, a is acceleration, x is position, and xo is the ...

Solution Summary

The answers are determined by looking at the relationships between velocity and acceleration and frictional force. The minimum coefficient of friction and the horizontal/vertical forces are calculated by using all these parameters and the variable of time.

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