Questions and Answers
What is the net force on a box pushed to the right with 50 N of force while being pushed to the left with 20 N of force?
30 N to the right
What two quantities are necessary for a vector quantity?
direction and magnitude
What can be said about the forces acting on an object that is at rest?
are opposite in direction, are equal in magnitude, and have a vector sum of zero
How much tension is there in a vertical rope that holds a 20-N bag of apples at rest?
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What is the acceleration of an object in free fall at Earth's surface?
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A car is traveling with constant velocity. This means that _______.
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A stone is dropped off a cliff and is in free fall. Every second that the stone is falling, its acceleration _______.
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By how much would a speedometer reading increase every second for an object in free fall?
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As an object freely falls, its ___ increases.
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At the end of two seconds of free fall, an object released from rest will have a speed of:
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When she hikes a distance of 1 km in a time of one-half hour, her average speed is?
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An object is pulled with two forces, 10 N northward and 15 N southward. The direction of the net force is to the?
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Where is your weight greater: on Earth or on the Moon? How about your mass?
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Mass is a measure of _______.
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If you pull on a box with a force of 5 N and your teacher pulls on the same box with a force of 5 N in the opposite direction, the net force on the box is _______.
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An object is at rest. The forces acting on the object _______.
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What is the acceleration of an object in free fall at Earth's surface?
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A free-falling object has a speed of 30 m/s at one instant. Exactly 2 seconds later, its speed will be?
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Compared with a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much _______.
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It is important to know that the term inertia refers to _______.
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What is the net force that acts on a 10-N freely falling object?
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A heavy parachutist has a greater terminal speed compared with a lighter parachutist with the same size parachute because the heavier person _______.
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Newton's second law of motion links force, acceleration, and _______.
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Whenever one object exerts a force on a second object, the second object exerts a force on the first that _______.
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When two horizontal forces are exerted on the car, 250 N forward and 230 N backward, what is the amount of acceleration?
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What is Newton's first law?
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What is Newton's second law?
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What is Newton's third law?
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What is the net force acting on a falling 1-kg ball if it encounters 2 N of air resistance?
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Is inertia a property of matter or a force of some kind?
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Newton's second law of motion links force, acceleration, and _______.
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If you are learning to juggle it would be good to slow the ball's acceleration. You can do this by using ______.
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Study Notes
Net Force
- Net force on a box pushed with 50 N right and 20 N left is 30 N right.
- Forces acting on a stationary object are equal and opposite, resulting in a vector sum of zero.
Vector Quantities
- Vector quantities require both direction and magnitude for their complete description.
Tension
- Tension in a vertical rope holding a 20-N object at rest is 20 N.
Free Fall
- Acceleration of an object in free fall at Earth's surface is 9.8 m/s².
- Free-falling stone’s acceleration remains constant while its velocity increases each second by 9.8 m/s.
- A free-fall object will have its speed increase by 9.8 m/s each second.
Motion Consistency
- An object with constant velocity moves in a straight line with no change in speed.
Comparing Mass and Weight
- A 2-kg block of iron has no similarities compared to a 1-kg block in terms of density or volume, but it has double the mass.
- Mass remains constant regardless of location; weight is greater on Earth compared to the Moon.
Inertia and Force
- Inertia refers to matter's resistance to changes in motion.
- If equal forces act on a box from opposite directions (5 N each), the net force is 0 N.
Dynamics of Forces
- An object experiences a net force of 10 N while freely falling, which matches its weight.
- Total net force on a car from 250 N forward and 230 N backward results in 20 N backward.
Newton's Laws of Motion
- Newton’s first law describes inertia; an object at rest remains at rest unless acted upon.
- Newton's second law relates force, mass, and acceleration.
- Newton's third law states that every action has an equal and opposite reaction.
Falling Objects and Resistance
- A falling object with 2 N of air resistance has a net force of 7.8 N.
- Heavier parachutists have greater terminal speeds since they must fall faster to equalize weight with air resistance.
Acceleration and Motion
- Speed readings for a free-falling object will yield a speed of 50 m/s two seconds after reaching 30 m/s.
- Average speed for a 1 km hike in 0.5 hours is 2 km/h.
Juggling Mechanics
- To slow the ball’s acceleration while learning to juggle, use heavier balls.
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Description
Test your understanding of fundamental physics concepts with these flashcards. Each card provides a question on topics such as net force and vector quantities. Perfect for students looking to reinforce their knowledge in physics.
