Motion Paractice part 2

Which term describes the tendency of a moving object to continue moving at the same velocity unless an unbalanced force acts on it?

• acceleration
• inertia  
• friction
• gravity

An index card is placed across the top of a drinking glass. A coin is then placed on top of the index card. A student quickly flicks the card sideways off the glass. Which of the following explains why the coin falls into the glass rather than moving to the side with the index card?

• Archimedes' Principle
• Newton’s law of universal gravitation
• Newton’s second  law of motion
• Newton’s first law of motion (Sometimes called the Law of Inertia)

Which of the following is an example of a force that acts at a distance?

• An airplane experiences friction as it moves through air.
• A book experiences a normal force as it rests on a table.
• A soccer ball experiences a force as it is kicked across a field.
• A magnet is pushed away when it is brought near the end of another magnet.

Why is the friction force considered to be a contact force?

• Friction affects only solid objects.
• Friction always acts in the same direction.
• Friction is produced when objects slide past one another. (they must make contact)
• Friction acts in a direction opposite to the direction of an object’s motion.

A box of books is on the floor. The following picture shows a push and a pull acting on the box. What is the net force toward the right on the box?

• 0 Newtons
• 50 Newtons
• 100 Newtons
• 2500 Newtons

During a baseball game, a hitter strikes the ball with a bat. When this happens, the ball and the bat exert a force on each other. Why does the ball accelerate away from the bat more than the bat accelerates away from the ball?

• The ball has less mass, so it exerts less force on the bat.
• The ball has greater velocity before the collision, so the force affects the ball more than it affects the bat.
• The bat exerts more force than the ball because the batter is exerting a force on the bat as it hits the ball.
• The ball has less mass, so the equal force on the ball and the bat causes greater acceleration of the ball.

The following picture shows forces acting on a sneaker. If the sneaker remains motionless, which statement is true?

• F and F_friction have equal strength.
• F_friction has greater strength than F.
• F, F_friction, F_gravity, and F_table all have exactly the same strength.
• F_table and F_friction have the same strength, and F and F_gravity have the same strength.

Imagine a box floating in space. The following picture shows all the forces acting on this box. What is the vertical force on this box?

• 50 N
• 100 N
• 150 N
• 200 N

Consider two objects whose masses are 100 g and 200 g. The smaller object strikes the larger object with a force of 500 N. According to Newton’s third law of motion, what force does the larger object exert on the smaller object?

• 1250 N
• 500 N because the reaction force is equal in magnitude to the action force.
• 250 N which is half the reaction force, which is equal in magnitude to the action force.
• 300 g times 500 N = total force of 150,000 N.

A moving object collides with a stationary object. Which of the following statements is true according to Newton’s third law of motion?

• Each object exerts a force on the other, and the two forces are equal and in opposite directions.
• Each object exerts a force on the other, and the two forces are the same in magnitude and direction.
• Each object exerts a force on the other, and the two forces are proportional to the masses of the objects.
• The moving object exerts a force on the stationary object, but the stationary object does not exert a force on the moving object.