Questions and Answers
If a system contains only two objects such as two stars, that exert a force on each other, then the net force on the system must be ____ since the system contains both the action and reaction forces.
zero
The amount of motion, that is, how much motion an object has, is called the object's ______.
momentum
A car traveling at 20 m/s eastward will have a momentum in the ____ direction.
eastward
If a Westward moving object experiences an impulse towards the East, it must now be moving Eastward.
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A puck slides along a frictionless surface in the northward direction. An eastward impulse is applied to the puck. The change in momentum of the puck is in the ____ direction.
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A dropped tennis ball bounces back upwards after striking the floor. The velocity thus went from downwards to upwards. The net force to cause this change in velocity must be upwards. The impulse must therefore be _____ in direction.
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When catching a ball, people tend to move their hands backwards with the ball a little bit. Doing so increases the time the hand exerts a stopping force on the ball, which means ___ overall force needs to be applied.
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The impulse-momentum principle relates the force multiplied by the time of the interaction (the impulse) with the change in the momentum of an object. This comes from a rearrangement of Newton's ___ law.
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The amount of motion (or quantity of motion) of an object is its ______.
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When a ball bounces against a wall, there will be a large change in velocity in a short period of time. This means the ____ is large, hence the net ___ must be proportionately large as well.
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The impulse on an object is the multiplication of the ____ multiplied by the ____.
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The momentum of an object depends on its ______.
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Rank the speed of each ball as it leaves the gun from fastest (top) to slowest (bottom): light ball, medium ball, heavy ball.
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Match the following situations with the type of collision on the right:
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When two objects collide inelastically, the energy can be lost by ______.
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A hard billiard ball elastically collides with another hard billiard ball of equal mass. Which situation is possible?
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Match the following situations with the type of collision on the right:
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What happens when two identical steel balls move straight towards each other at the same speed and elastically collide?
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In order for two objects to collide perfectly inelastically, they must ____ together after the collision.
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A piece of al dente pasta is thrown against the wall to see if it is cooked. Being cooked, the noodle sticks to the walls after its perfectly _____ collision.
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When a bat strikes a ball, which of the following are the same on both the bat and the ball?
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If the net external force on a system of objects is zero, then the total ___ is conserved.
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Study Notes
Force and Motion Concepts
- A system with two objects exerting forces on each other has a net force of zero, as action and reaction forces cancel out.
- The amount of motion of an object is termed its momentum, which is dependent on both mass and velocity.
- Momentum of an object can be described directionally; e.g., a car moving eastward has momentum in the eastward direction.
Impulse and Change in Velocity
- An impulse towards the east does not guarantee a westward object will move eastward after experiencing it; such a statement is false.
- When an eastward impulse is applied to a puck sliding northward, its change in momentum will be eastward.
Forces in Motion
- A tennis ball experiences an upward net force after bouncing from the floor, indicating that the impulse direction must also be upward.
- To catch a ball effectively, moving hands backwards increases contact time, ultimately requiring less force to stop the ball.
Impulse-Momentum Principle
- The impulse-momentum principle connects impulse (force × time) with changes in an object's momentum, derived from Newton’s second law.
- Impulse can be quantified as the product of net force and time interval during the interaction.
Kinetic Energy and Collisions
- Collisions vary based on energy conservation:
- Elastic collisions conserve total kinetic energy.
- Inelastic collisions involve energy loss via sound, deformation, or heat generation.
- Perfectly inelastic collisions result in objects sticking together after impact.
- Billiard balls in elastic collisions can produce situations where one stops and the other moves at the speed of the first ball.
Collision Outcomes and Examples
- Perfectly inelastic relationships occur when objects stick together post-collision, such as pasta adhering to a wall.
- Identical objects colliding elastically will bounce back with equal speeds but in opposite directions.
- In all collisions, the magnitudes of impulse, force, and time acted upon are the same for both objects involved.
Conservation of Momentum
- If the net external force on an object system is zero, the system’s total momentum remains conserved.
- During any collision scenario, directional movement is essential to determine potential outcomes based on energy principles and momentum conservation.
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Description
Test your understanding of force, motion, and momentum with this quiz. Explore the principles of impulse and how they relate to changes in velocity and direction. This quiz covers essential concepts in dynamics that are foundational to physics.