31 terms

Newton's Law - Conceptual

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The law of inertia states that an object...
Will continue moving at the same velocity, in a straight line, and will remain at rest if already at rest unless acted upon by an outside force
A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. The reason this can be done is because...
The milk carton has inertia
One object has twice as much mass as another object. The first object has twice as much...
Inertia
Compared to its weight on Earth, a 10-kg object on the moon will weigh...
Less
Compared to its mass on Earth, the mass of a 10-kg object on the moon is...
The same
What comes from microscopic bumps that act as obstructions to the object's motion, is the name given to the force acting between surfaces sliding past one another, and acts in a direction that opposes the motion of an object?
Friction
A girl's weight is 500 N as she hangs from the middle of a bar supported by two vertical strands of rope. What is the tension in each strand?
250 N
Friction is the force that always acts...
Opposite to an object's motion
The weight of a person can be represented by a vector that acts...
Straight down, even if the person is standing on a hill
A clothesline is stretched between two trees. A tire hangs in the middle of the line and the 2 halves of the line make equal angles with the horizontal. The tension in the line is...
More than half the tire's weight
Accelerations are produced by...
Unbalanced Forces/ Net force greater than zero
How does acceleration of an object change in relation to its mass?
They are inversely proportional
When an object reaches terminal velocity, its acceleration is...
0 m/s^2
A heavy person and a light person parachute together and wear the same size parachute. Assuming they open their parachutes at the same time, which person reaches the ground first?
The heavier person
A book weighs 4 N. When held at rest in your hands, the net force on the book is...
0 N
A tennis ball and a solid steel ball with the same diameter are dropped at the same time. Which ball has the greater force acting on it?
the steel ball because it has more mass. force of gravity= mass x 10m/s/s
A tennis ball and a solid steel ball with the same diameter are dropped at the same time. In the absence of air resistance, the steel ball accelerates downwards at 10m/s/s. How fast will the tennis ball accelerate?
the tennis ball will have the same acceleration.
The reason a tennis ball and a solid steel ball will accelerate at the same rate in the absence of air resistance is because...
The ball with the larger force also has the greater mass, meaning more inertia
If the force acting on a cart doubles, what happens to the cart's acceleration?
Doubles
Suppose a cart is being moved by a force. If a load is suddenly dumped into the cart so the its mass doubles, what happens to the cart's acceleration?
Is divided in half
A player catches a ball. Consider the action force to be the impact of the ball against the player's glove. What is the reaction to this force?
The force the glove exerts on the ball
A bug splatters against the windshield of a moving car. Compared to the force of the car on the bug, the force of the bug on the car is...
The same as the force of the car on the bug
A bug splatters against the windshield of a moving car. Compared to the deceleration of the car, the deceleration of the bug is
Larger than the deceleration of the car
According to Newton's Third Law, if you push gently on something it will...
Push gently on you
A skydiver dives towards Earth. The attraction of Earth on the skydiver pulls him down. The reaction to this force is...
The skydiver pulling up on earth
A rocket is able to accelerate in the vacuum of space when it fires its engines. The force that propels the rocket is the...
Force of the exhaust gases on the rocket
A karate chop delivers a blow of 2300 N to a board that breaks. The force that acts on the hand during this feat is...
2300 N
Suppose you are on an airplane moving at high speed. If you flip a coin straight up, it will land in your lap rather than a great distance behind you. Explain why.
The coin and you are accelerating at the same rate; therefore, it moves as you move, even if tossed in midair
Explain why the acceleration of two free-falling objects that have different masses is the same. Is the force on each mass the same as well?
The force on each mass is different because the masses are not the same, but the acceleration is the same because they are free-falling and gravity is working equally on both objects
Explain how Newton's Third Law applies to a cannon launching a cannonball. Which has the larger acceleration, the cannonball or the cannon? What if the cannonball were just as massive as the cannon - how fast would the cannon move compared to the cannonball?
The cannon, while applying much force to the cannonball, also has much force exerted back from the cannonball. Every action has an equal and opposite reaction. Because the cannon's mass is greater, the cannonball has a larger acceleration. If they were both equal in mass, the would accelerate at the same rate
If two forces are acting on a different object, will the action - reaction forces cancel each other out? What if they are acting on the same object?
If acting on different objects - don't cancel each other out
If acting on the same object - cancel each other out