Forces: Understanding Force Diagrams Quiz

Olivia is helping her friend move a heavy box. In a force body diagram, which of the following is typically used to represent the forces Olivia applies to the box?

• Circles

• Arrows

• Squares

• Dots

Answer explanation

In a force body diagram, forces are represented by arrows. The direction of the arrow indicates the direction of the force, while the length represents its magnitude. Therefore, Olivia's applied forces to the box are shown as arrows.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

If a box is being pushed to the right with a force of 10 N and there is a frictional force of 3 N acting to the left, what is the net force acting on the box?

• 7 N to the right

• 13 N to the right

• 7 N to the left

• 3 N to the left

Answer explanation

To find the net force, subtract the frictional force from the applied force: 10 N (right) - 3 N (left) = 7 N to the right. Thus, the net force acting on the box is 7 N to the right.

Tags

NGSS.MS-PS2-2

Which of the following scenarios describes balanced forces?

• A car accelerating on a highway

• A book resting on a table

• A ball rolling down a hill

• A person pushing a wall and moving it

Answer explanation

Balanced forces occur when all forces acting on an object are equal and opposite, resulting in no movement. A book resting on a table has equal gravitational and normal forces, making it a scenario of balanced forces.

What is the effect of friction on a moving object?

• It speeds up the object

• It slows down the object

• It changes the direction of the object

• It has no effect on the object

Answer explanation

Friction opposes the motion of a moving object, causing it to lose energy and slow down. Therefore, the correct answer is that friction slows down the object.

In a force body diagram, which force is always directed towards the center of the Earth?

• Tension

• Normal force

• Gravitational force

• Frictional force

Answer explanation

The gravitational force is always directed towards the center of the Earth, pulling objects downwards. This force is responsible for the weight of an object and is distinct from tension, normal, and frictional forces.

Tags

NGSS.MS-PS2-4

A box is at rest on a flat surface. Which of the following statements is true about the forces acting on the box?

• The forces are unbalanced

• The net force is zero

• The gravitational force is greater than the normal force

• The frictional force is greater than the gravitational force

Answer explanation

The box is at rest, meaning all forces acting on it are balanced. The gravitational force is equal to the normal force, and there is no net force acting on the box, making the net force zero.

If a force of 5 N is applied to the right and a force of 5 N is applied to the left on an object, what can be said about the forces?

• They are balanced

• They are unbalanced

• The net force is 10 N to the right

• The net force is 10 N to the left

Answer explanation

The forces of 5 N to the right and 5 N to the left are equal in magnitude and opposite in direction. This means they cancel each other out, resulting in no net force. Therefore, the forces are balanced.

Tags

NGSS.MS-PS2-2

Which of the following is an example of an unbalanced force?

• A book lying on a table

• A car parked on a hill

• A person running

• A picture hanging on a wall

Answer explanation

A person running is an example of an unbalanced force because they are exerting force to move, overcoming inertia. In contrast, the other options involve balanced forces where no net movement occurs.

Tags

NGSS.MS-PS2-2

What happens to the net force on an object if two equal forces act on it in opposite directions?

• The net force increases

• The net force decreases

• The net force becomes zero

• The net force doubles

Answer explanation

When two equal forces act in opposite directions, they cancel each other out. This results in a net force of zero, as the forces are balanced.

Tags

NGSS.HS-PS2-1

Which force opposes the motion of an object sliding on a surface?

• Gravitational force

• Tension force

• Frictional force

• Normal force

Answer explanation

The frictional force opposes the motion of an object sliding on a surface by acting in the opposite direction to the movement, thereby slowing it down or stopping it.