PSc.1.2.3

This diagram shows a 40-kg object being pulled in one direction while friction acts on it in the opposite direction. What is the net force on the object?

• 160 N

• 140 N

• 120 N

• 20 N

A 1,500-kg truck has a net force of 4,200 N acting on it. What is the truck’s acceleration?

• 6,300,000 m/s/s

• 2,700 m/s/s

• 2.8 m/s/s

• 0.36 m/s/s

The action of swimmers using their arms to propel themselves through the water is an example of what law?

• Newton’s first law of motion

• Newton’s third law of motion

• law of conservation of linear momentum

• law of conservation of angular momentum

A smooth card is placed over a drinking glass. A penny is placed in the middle of the card. When the card is hit with the index finger, the card moves away, and the penny drops into the glass. Which statement BEST explains why the penny does not move in the same direction as the card?

• There is an absence of friction between the penny and the card.

• There is a little gravity between the card and the penny.

• The card exerts too much force on the penny.

• The penny has more inertia than the card.

During a classroom discussion on motion, the teacher instructs the class to write down something that specifically addresses Isaac Newton’s second law of motion. Which of these responses would BEST represent the second law?

• For every action there is an equal and opposite reaction.

• Every object continues at rest unless acted on by outside forces.

• Acceleration depends on the force applied and the mass of an object.

• Every object attracts every other object and the force is proportional to their masses.

A student measures the mass of a lead weight. She then applies a force of known magnitude in pushing the weight over a smooth surface. She measures the acceleration of the weight when acted on by the force. Which would be the BEST hypothesis for this investigation?

• Velocity is constant when air resistance balances weight.

• For every action force, there is an equal and opposite reaction force.

• An object in motion maintains its velocity unless it experiences an unbalanced force.

• The unbalanced force acting on an object equals the object’s mass times its acceleration.

A horizontal force of 24 N is being applied to a box on a level surface. The box is accelerating at the rate of 2.0 m/s2 against a frictional force of 14 N. What is the mass of the box?

• 5.0 kg

• 7.0 kg

• 12 kg

• 19 kg

A 3.0 N force and a 5.0 N force are acting in opposite directions on the same 5.0 kg ball. What is the magnitude of the acceleration of the ball?

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• 
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A student pushes a book with a force of 5 N to the east. Which statement describes the reaction force?

• 5N eastward, acting on the book

• 5N westward, acting on the book

• 5N eastward, acting on the student

• 5N westward, acting on the student

Which of these causes matter to resist a change in motion?

• inertia

• friction

• gravity

• weight