Newton’s laws of motion

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A. also 40 m/s.

45 m/s.

50 m/s.

none of the above.

Newton’s Second Law of Motion

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Slide 19

At one instant an object in free fall has a speed of 40 m/s. Its speed one second later is

A. also 40 m/s.

45 m/s.

50 m/s.

none of the above.

Explanation:

We assume the object is falling downward.

Newton’s Second Law of Motion

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Slide 20

Newton’s Second Law of Motion

When acceleration is g—free fall.

Twice the force on twice the mass 

same acceleration as half the force on half the mass.

Slide 21

A 5-kg iron ball and a 10-kg iron ball are dropped from rest. For negligible air resistance, the acceleration of the heavier ball will be

A. less.

the same.

more.

undetermined.

Newton’s Second Law of Motion

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Slide 22

A 5-kg iron ball and a 10-kg iron ball are dropped from rest. For negligible air resistance, the acceleration of the heavier ball will be

A. less.

the same.

more.

undetermined.

Newton’s Second Law of Motion

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Slide 23

A 5-kg iron ball and a 10-kg iron ball are dropped from rest. When the free-falling 5-kg iron ball reaches a speed of 10 m/s, the speed of the free-falling 10-kg iron ball is

A. less than 10 m/s.

10 m/s.

more than 10 m/s.

undetermined.

Newton’s Second Law of Motion

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Slide 24

A 5-kg iron ball and a 10-kg iron ball are dropped from rest. When the free-falling 5-kg iron ball reaches a speed of 10 m/s, the speed of the free-falling 10-kg iron ball is

A. less than 10 m/s.

10 m/s.

more than 10 m/s.

undetermined.

Newton’s Second Law of Motion

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Slide 25

Newton’s Second Law of Motion

When acceleration is g—free fall.

The ratio of weight to mass is the same for all falling objects in the same locality; hence, their accelerations are the same in the absence of air resistance.

Slide 26

Newton’s Second Law of Motion

When acceleration is g — free fall.

Demonstration of a feather and a coin in a vacuum.

In a vacuum, a feather and a coin fall together at g—the acceleration due to gravity.