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1**
Which two graphs represent
the motion of an object on which the net force is zero?

**
**

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**2**
The table below lists the
coefficients of kinetic friction for four materials sliding over
steel.

A 10.-kilogram block of each of these materials is pulled horizontally across a steel floor at constant velocity. Which block requires the smallest applied force to keep it moving at constant velocity?

(1) aluminum (3) copper

(2) brass
(4) steel

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(1) 5.0 N (3) 50. N

(2) 10. N (4) 250 N

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**4** A bullet traveling at 5.0 ×
102 meters per second is brought to rest by an impulse of 50.
newton•seconds. What is the mass of the bullet?

(1) 1.0 × 10^{–2} kg (3) 1.0
× 10^{1} kg

(2) 1.0 × 10^{–1} kg (4) 2.5
× 10^{4} kg

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**5 **Which graph best represents
the relationship between acceleration due to gravity and mass for
objects near the surface of Earth? [Neglect air resistance.]

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