Spring Forces AP Style Practice

A block on a horizontal surface is attached to two horizontal springs, as shown. Both springs are compressed a distance Δx from their unstretched length and the block remains at rest due to static friction between the block and the surface. Which of the following is a correct expression for the magnitude of the force of static friction?

Answer explanation

In scenarios A, B, and C, shown in the figure, blocks with the masses indicated are attached to identical vertical springs. The block in each scenario is slowly lowered until it reaches equilibrium. Which of the following correctly ranks the distances ΔxA, ΔxB, and ΔxC that each block is lowered?

• Δx_B > (Δx_A = Δx_C)

• Δx_C > Δx_A > Δx_B

• (Δx_A = Δx_B) > Δx_C

• Δx_C > (Δx_A = Δx_B)

Tags

NGSS.HS-PS2-1

A block is attached to one end of a horizontal ideal spring whose other end is attached to a wall. The spring is initially unstretched and its right end is at position x = 0. The block is then pulled until it is at a position x = +A, as shown in Figure 1, where the spring exerts a force of magnitude F on the block. The spring is then moved to a position x = -A, as shown in Figure 2. Which of the following correctly indicates the magnitude and direction of the force the spring exerts on the block in Figure 2?

• F to the left

• F to the right

• 2F to the left

• 2F to the right

Answer explanation

Tags

NGSS.HS-PS2-1

Answer explanation

Tags

NGSS.HS-PS2-1

A block of mass m hangs in equilibrium from an ideal spring inside an elevator, as shown. The elevator moves downward at a constant speed and the length of the spring is x₁. The elevator then gradually slows to a stop with constant acceleration. Which of the following statements correctly describes the length of the spring while the elevator is decelerating?

• It is constant and equal to x₁.

• It is constant and greater than x₁.

• It is constant and less than x₁.

• It starts off greater than x₁ and slowly decreases.

Answer explanation

Tags

NGSS.HS-PS2-1

A block hangs at rest from a spring, stretching the spring to length L, as shown in the left figure. The block is then completely submerged in a tank of water and comes to rest, as shown in the right figure. It is observed that, with the block in the water, the spring’s length is less than L. Which of the following correctly indicates why the spring’s length decreases when the block is submerged?

• The spring constant decreases.

• The spring constant increases.

• The block has less weight.

• There is an additional force exerted on the block.

Answer explanation

Tags

NGSS.HS-PS2-1

Which of the following statements about the motion of the weight must be true whenever the weight is between points B and C?

• The weight’s acceleration is downward.

• The weight’s acceleration is upward.

• The weight’s velocity is downward.

• The weight’s velocity is upward.

Answer explanation

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

A student uses a force probe to exert varying forces on the ends of vertical springs A, B, and C. The student then sketches the magnitude of the applied force as a function of the length of the spring for each spring, as shown. Which of the following correctly compares the spring constants k of each spring?

• k_B > k_C > k_A

• k_B > k_A > k_C

• k_C > k_B > k_A

• k_A > k_B > k_C

Answer explanation

Which of the following correctly relates x₂ to x₁?

Answer explanation