Forces NCFE Review

Why does a flat piece of notebook paper take longer to reach the ground than an identical piece of notebook paper crumpled into a ball?

• The flat piece of paper has more mass.

• The crumpled piece of paper has more mass.

• The frictional force of air has more effect on the falling flat piece of paper.

• The frictional force of air has more effect on the falling crumpled piece of paper.

Tags

NGSS.MS-PS2-2

Why does the weight of an object change with increasing elevation on Earth?

• The mass of the object decreases with higher elevation.

• The force of gravity acting on the object increases with higher elevation.

• The force of gravity acting on the object decreases with higher elevation.

• The mass of the object increases with higher elevation.

Which type of friction occurs when an eraser is rubbed across a sheet of paper?

• static

• sliding

• rolling

• fluid

Two students pull on the opposite ends of a rope, but neither student is able to move the other. Which statement best explains why neither student is moved?

• They each pull on the rope with the same amount of force, so the net force is zero.

• They each exert the same amount of friction against the ground, so the net friction is zero.

• Their forces are not balanced, but gravity keeps them from moving.

• The two students have the same mass.

Tags

NGSS.MS-PS2-1

A rock on Earth has a mass of 750 kg and a weight of 7,350 N. If the rock is taken into outer space, how will its mass and weight be affected?

• The weight and mass will remain the same because they are not altered by the effects of gravity.

• The weight will remain the same, but the mass will change because of the effects of gravity.

• The mass will be 76.5 kg, and the weight will increase because of the effects of gravity.

• The mass will be 750 kg, but the weight will decrease because of the effects of gravity.

As the wheels of a train move along the train tracks, what type of friction exists between the wheels and the tracks?

• fluid friction

• rolling friction

• sliding friction

• static friction

A 1,500-kg truck has a net force of 4,200 N acting on it. What is the truck’s acceleration?  $a=\frac{\left(v_f\ -\ v_i\right)}{t}$  

• 6,300,000 m/s/s

• 2,700 m/s/s

• 2.8 m/s/s

• 0.36 m/s/s

Tags

NGSS.MS-PS2-2

This diagram shows a 40-kg object being pulled in one direction while friction acts on it in the opposite direction? What is the net force on the object?

• 160 N

• 140 N

• 120 N

• 20 N

Tags

NGSS.MS-PS2-2

Student X pushes a 10-N box with a force of 2 N. At the same time, Student Y pushes the same box with a force of 6 N, but in the opposite direction. Which would most likely occur? (Ignore friction)

• The resultant force on the box would be 8 N.

• The resultant force on the box would be 18 N.

• The box will move toward Student X.

• The box will move toward Student Y.

Tags

NGSS.MS-PS2-2

This diagram shows three horizontal forces acting on an object. Ignoring friction, what is the magnitude of force, F, if the object remains at rest?

• 6 N

• 8 N

• 14 N

• 22 N

Tags

NGSS.MS-PS2-2