Select which of the following statements are True or False. Assume Newtonian Mec

Question

Select which of the following statements are True or False. Assume Newtonian Mechanics.
True or False  The power required to lift a mass does not depend on the speed at which the mass is raised.
True or False  The acceleration of an object is same in all inertial reference frames.
True or False  The work required to lift a mass one meter depends on the speed at which it is raised..
True or False  The work done by a constant force acting on an object is equal to the magnitude of the force times the distance the object moves.
True or False  A particle's kinetic energy can change without having any net work done it.
True or False  A simple machine cannot reduce the work required to do a task.

Explanation / Answer

1.  False. The power depends on how much mass, the local gravitational field, and the elevation change desired.

2. True. An inertial reference frame is a reference frame which isn't accelerating.

3. False. The work required depends on how much mass, the local gravitational field, and the elevation change desired.

4. Almost true, but technically FALSE. You forgot the cosine of the angle between the vectors term.

I can apply a force and have an object move, but do no work on it, if I apply the force perpendicular to the direction of motion.

To make it true:
"The work done by a constant force acting on an object is equal to the aligned component of a force times the distance the object moves."

5. False( work need to be done to change velocity and hence kinetic energy { workdone = 0.5xm(v2-u2) } )

6. False. Simple machines enable trade of force and distance. At the input of a simple machine, a small force is required and at the output, a large force is delivered. We pay for this, because at the input, a large distance of application of the force is required, and at the output, only a little distance is delivered.

It could be made false, if you design a simple machine for a different purpose. If you design a simple machine like overdrive gearing of a large gear driving a small gear, the input is a large force through a small distance, and the output is a small force applied through a large distance. Such a simple machine still is useful, it just isn't the majority of simple machines.

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