A coin is sitting on an index card which is resting on a cup. A force is exerted on the card and the coin falls down. Is science magic? Using one or more of Newton’s laws, explain why the card AND the coin moved the way they did.
Question 10
10.
Marty and Biff are at the local frozen pond. Marty thinks it would be funny to sneak up behind Biff and give him a big push forward. Would Newton think this is a good idea? Using one or more of Newton’s laws, explain why you think so.
Inertia is _____.
a property of objects that describes their tendency to keep doing what they are already doing
something that describes heavy objects but not light objects
a force that resists changes in motion
a force that resists all movement
What would happen to objects on Earth if our planet suddenly stopped spinning and came to an immediate halt?
because every object has inertia, objects will stop along with the Earth
because every object has inertia, objects will resist any changes to their motion, pushing back on Earth
because every object has inertia, objects will gradually slow to a stop like everything else on Earth
because every object has inertia, objects would continue moving when Earth stopped, leading to possible destruction and injury
A box is sitting at rest on the floor. A boy pushes on the box with a force of 10 N. The frictional force between the box and the floor is 2 N. Which statement is true?
because the boy’s push is opposed by friction, the box will not move at all
objects at rest tend to stay at rest, so the box will not move because of inertia
there is an unbalanced force on the box, so it will accelerate
the box has inertia which will resist the boy’s push, so the box’s inertia will push back on the boy
A train is moving along a straight section of track at a constant speed. Which statement is true?
if the train is moving at a constant speed, there must be no forces acting on the train
the train must have a force acting on it that is larger than the train’s inertia to keep it moving
there must be an unbalanced force acting on the train to keep it moving at a constant speed
if the train is moving at a constant speed, then any forces acting on the train must cancel each other out
You hit a ball with a baseball bat. What keeps the ball moving after it leaves the bat?
the unbalanced force acting on the ball keeps it moving
the force of gravity. If you could turn off gravity, the ball would stop
the ball doesn’t need anything to keep moving. It does this all by itself due to its inertia
the force of the bat keeps the ball moving through the air
You apply a very small net force, say 0.1 N to a very large truck, with a mass of 2000 kg. Which statement is true?
the truck will move as long as the tiny force is larger than any force of friction that opposes it
an extremely small force can never accelerate such a large truck; the truck will never move
the truck cannot move because small forces cannot move large objects
the truck will move as long as the tiny force is larger than the force of inertia acting on the truck
Someone throws you a baseball and you catch it with a baseball glove, exerting a force of 6 N in order to bring the ball to a stop. What do you know about the force the ball exerts on the glove?
the force the ball exerts on the glove must be larger than the force the glove exerts on the ball since it’s the object moving
it’s impossible to answer this without knowing the mass of the ball and the speed of the ball before impact
the force the ball exerts on the glove is smaller than the force the glove exerts on the ball because the ball stops
the ball exerts a force of 6 N on the glove. Newton’s third law tells us that the forces are equal and opposite
Violent collisions are part of the game of football. Besides penalties for dangerous hits, which of the following is true with respect to these collisions?
the player tackling a running player will always hit the runner with a greater force since he has more momentum
the player with the larger mass always has the most momentum, so he hits the other player with a larger force
the player running at a tackler will always hit the tackler with a greater force since he has less momentum
no matter who is getting hit, each player in the collision receives the same force because of the conservation of momentum