Scientists use specific processes to evaluate information in order to determine its accuracy and reliability. A scientist is con
2 answers:
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Answer:
Explanation:
Static friction occurs when an object initially starts at rest. When the surfaces of the materials touch, the microscopic unevenness interlock greatest with each other, causing the most friction out of the three.
During sliding friction, an object is already moving or in motion. The microscopic surfaces still interlock, but because the object is in motion, it has a momentum. Therefore, the magnitude of sliding friction is less than that of static friction.
Rolling friction occurs when an object rolls across some surface. Rather than surfaces interlocking, rolling friction is caused by the constant distortion of surfaces. As it rolls, the surfaces of the object are constantly wrapping and changing. This distortion causes the rolling friction. However, it is much less in magnitude when compared to static or sliding friction.
Answer:
a) 1.89 m/s b) 172.1 N
Explanation:
a)
- Applying the work-energy theorem, if we can neglect the friction between truck and road, the total change in kinetic energy must be equal to the work done by the external forces.
- This work, is just 4,475 J.
- So we can write the following equation:
- where m= mass of the truck = 2.5*10³ kg.
- So, we can find the speed v, as follows:
b)
- The work done by the man, is just the horizontal force applied, times the displacement produced by the force horizontally:
- We can solve for F, as follows: