Warm-Up Exercise 2

Due 2:00 pm, Tuesday, January 13

Physics 105, Winter Semester, 2009

Newton's first law states that, in the absence of any forces, an object in motion will
remain in motion forever or
eventually come to rest.

Consider two objects with the same mass. If one object is moving and the other object is not, which object has the most inertia?
the object which is moving
the object which is not moving
Both objects have the same inertia.

If I push on an object which is at rest (like the wall), then the force exerted by my hand on the object will be equal to the force exerted by the object on my hand. However, if I push on an object, causing it to accelerate, then the force exerted by my hand on the object will be
greater than,
less than, or
still equal to
the force exerted by the object on my hand.

The force required to maintain an object at a constant speed in free space is equal to
the mass of the object,
the weight of the object,
zero,
the force required to stop it, or
none of the above.

Ralph asked me a question the other day. Suppose he's driving his car and a bug hits his windshield. The bug is totally smashed, but the windshield is unaffected. Doesn't this mean that the force exerted by the windshield on the bug is greater than the force exerted by the bug on the windshield? How would you answer his question? Be sure to explain why.

Ralph told me he was thinking about the penny and feather falling in a vacuum. The penny and feather both fell at the same rate. He asked, "Does this mean that the force on the penny and the force on the feather are equal?" How would you answer his question? Be sure to explain your answer.

Was there anything that you didn't understand in the reading assignment?

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