PS2.1 Forces and Motion

Examine the diagram. The sailboat is powered by a fan. If the force of the fan stops, what will most likely happen to the motion of the boat?

• The boat will change direction.

• The boat will travel a greater distance.

• The boat will speed up.

• The boat will slow down.

Answer explanation

If the force of the fan stops, the boat will no longer be propelled forward. As a result, it will gradually slow down due to friction and water resistance, making 'The boat will slow down' the most likely outcome.

Tags

NGSS.MS-PS2-2

A force is applied to move a box, as shown. Which statement best describes how and why the box will move?

• The box will move to the left because the forces are unbalanced.

• The box will move to the right because the forces are unbalanced.

• The box will move to the left because the forces are balanced.

• The box will move to the right because the forces are balanced.

Answer explanation

The box will move to the left because the applied force is greater than any opposing forces, making the forces unbalanced. This results in a net force that causes the box to accelerate to the left.

Tags

NGSS.MS-PS2-2

Which diagram shows an object at rest?

• 
• 
• 
• 

A student records measurements and observations from two tests in a table. Which question is the student likely testing?

• How do balanced forces impact the final speed?

• How do unbalanced forces impact the direction of motion?

• How do balanced forces impact the speed of motion?

• How do unbalanced forces impact the initial speed?

Answer explanation

The student is likely testing how unbalanced forces affect motion, specifically direction, as unbalanced forces cause changes in direction. The other options focus on speed, which is not the primary concern in this context.

Tags

NGSS.MS-PS2-2

A student rolls downhill on a bike. When the student uses the brakes, the bike stops. Why does the bike stop when the student uses the brakes?

• The brakes create an unbalanced force by creating a force in the direction of motion.

• The brakes create an unbalanced force by creating a force opposite the direction of motion.

• The brakes create a balanced force by creating a force opposite the direction of motion.

• The brakes create a balanced force by creating a force in the direction of motion.

Answer explanation

The bike stops because the brakes create an unbalanced force opposite to the direction of motion, which slows down and eventually stops the bike.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS3-5

A person pushes a chair on the ground to the right with a force of 4 N. Which two additional forces will maintain or increase the speed of the moving chair?

• force of friction

• force of gravity

• force of 0 N to the right

• force of 3 N to the right

• force of 4 N to the left

Answer explanation

To maintain or increase the chair's speed, additional forces must also act to the right. A force of 0 N to the right means no opposing force, while a force of 3 N to the right adds to the initial 4 N, ensuring acceleration.

Tags

NGSS.MS-PS2-2

A grocery cart rolls in a flat parking lot with a constant force of 3 N. How much force is needed for a shopper to stop the motion of the grocery cart?

• 1 N

• 2 N

• 3 N

• 4 N

Answer explanation

To stop the grocery cart, the shopper must apply a force equal to the force causing its motion. Since the cart is moving with a constant force of 3 N, the shopper needs to exert a force of 3 N in the opposite direction to stop it.

Tags

NGSS.MS-PS2-2

A grocery cart rolls in a flat parking lot with a constant force of 3 N. What type of force is needed to change the direction of motion of the grocery cart?

• A smaller force in the same direction.

• A smaller force in the opposite direction.

• A larger force in the same direction.

• A larger force in the opposite direction.

Answer explanation

To change the direction of the grocery cart, a larger force in the opposite direction is needed to overcome the existing force of 3 N and alter its motion.

Tags

NGSS.MS-PS2-2

A student places four blocks of different masses on a balance beam. The student claims that the forces acting on the blocks are balanced. Which statement supports the claim?

• Friction pushes left on the blocks with the same force as the balance beam pushes right.

• Gravity pulls down on the blocks with the same force as the balance beam pushes up.

• The balance beam has the same mass as all the blocks combined.

• The balance beam moves when the student places the blocks on it.

Answer explanation

The correct statement highlights that the upward force from the balance beam matches the downward gravitational force on the blocks, indicating that the forces are balanced.

Tags

NGSS.MS-PS2-4

A student tests the impact of different forces on the speed of a toy car while it moves to the right. The student records the forces applied to the moving car and the results in a table. Which conclusion do the results best support?

• The speed is fastest when a balanced force is applied in the direction of motion.

• The speed is fastest when a balanced force is applied in the direction opposite the motion.

• The speed is fastest when an unbalanced force is applied in the direction of motion.

• The speed is fastest when an unbalanced force is applied in the direction opposite the motion.

Answer explanation

The results support that the speed is fastest when an unbalanced force is applied in the direction of motion, as unbalanced forces increase acceleration, leading to higher speeds.

Tags

NGSS.MS-PS2-2