NC Forces and Motion

A student pushes a box with a force of 15 newtons (N) to make it slide across the floor. Once the box starts moving, a frictional force of 5 N acts upon it.
If the student continues to push the box with a force of 15 N, what will happen to the box?

• The box will stop moving forward.
• The box will move forward at a steady speed.
• The box will move forward at a decreased speed.
• The box will move forward at an increasing speed.

Sally ran a distance of 8 m in 16 s. The graph below shows her motion.

• Her speed was constantly changing.
  
• Her speed remained constant.
• She stopped moving after four seconds.
• She decreased her speed after four seconds.

Two students pull on a rope with 100 N in opposite directions. If the student on the left increased her force to 125 N, the rope would MOST likely...

• go from rightward acceleration to leftward acceleration.
• go from motionless to leftward acceleration.
• decrease its leftward acceleration.
• decrease its rightward acceleration.

A wagon is pulled to the right using a force of 20 N and to the left using a force of 30 N. What is the net force on the wagon?

• 10 newtons to the left
• 50 newtons to the left
• 10 newtons to the right
• 50 newtons to the right

In order for a rope to anchor a boat in place, the rope must exert a force

• equal to the force exerted by the water current in the opposite direction.
• equal to the force exerted by the water current in the same direction.
• greater than the force exerted by the water current in the opposite direction.
• greater than the force exerted by the water current in the same direction.

Gravity is a measurable force of attraction which acts upon objects. Which characteristic determines the gravity of an object?

• friction
• mass
• tension
• weight

In a game of tug-of-war, the people on each team pull with the amount of force shown. In which direction will the center of the rope go?

• to the west because the net force is greater in this direction
• to the east because the net force is greater in this direction
• to the west because the net force is less in this direction
• to the east because the net force is less in this direction

Two forces are applied to a wooden box as shown below. Which statement BEST describes the effect these forces have on the box?

• The box does not move.
• The box moves to the right.
• The box moves to the left.
• The box moves straight up.

Which statement BEST explains why a car that is rolling on a level surface will eventually come to a stop?

• Frictional forces oppose the motion of the car.
• Forward motion slowly runs out as energy is expended.
• The natural state of an object is to be at rest.
• Inertia acting on an object will dissipate.

Two forces act in opposite directions on a wood block. What will happen if the forces are unbalanced?

• The block will balance the forces.
• The forces will reverse direction.
• The mass of the block will change.
• The position of the block will change.