Dynamics

A ball of mass m is suspended from two strings of unequal length as shown above. The magnitudes of the tensions T1 and T2 in the strings must satisfy which of the following relations?

•  T1 = T2
• T1 > T2
•  T1 < T2
•  Tl + T2 = mg

Tags

NGSS.HS-PS2-1

Which of the following correctly indicates the magnitudes of the forces acting up and down the incline?

• 20 N down the plane, 16 N up the plane
• 4 N down the plane, 4 N up the plane
• 0 N down the plane, 4 N up the plane
• 10 N down the plane, 6 N up the plane

Tags

NGSS.HS-PS2-1

A horizontal, uniform board of weight 125 N and length 4 m is supported by vertical chains at each end. A person weighing 500 N is hanging from the board. The tension in the right chain is 250 N.

• 125 N 
• 250 N
• 375 N 
• 625  N

Tags

NGSS.HS-PS2-1

Which of the following describes where the person is hanging?

•  between the chains, but closer to the left-hand chain
•  between the chains, but closer to the right-hand chain
•  Right in the middle of the board
•  directly below one of the chains

A wooden box is first pulled across a horizontal steel plate as shown in the diagram A. The box is then pulled across the same steel plate while the plate is inclined as shown in diagram B. How does the force required to overcome friction in the inclined case (B) compare to the horizontal case (A)?

• the frictional force is the same in both cases
• the inclined case has a greater frictional force
• the inclined case has less frictional force
• the frictional force increases with angle until the angle is 90º, then drops to zero

When the frictionless system shown above is accelerated by an applied force of magnitude the tension in the  string between the blocks is 

• F 
• 2/3 F
• ½ F 
• 1/3 F

Tags

NGSS.HS-PS2-1

A block of weight W is pulled along a horizontal surface at constant speed v by a force F, which acts at an angle of θ with the horizontal, as shown above. The normal force exerted on the block by the surface has magnitude

• greater than W
• greater than zero but less than W
• equal to W
• 0

Tags

NGSS.HS-PS2-1

Two massless springs, of spring constants k₁ and k_2, are hung from a horizontal support. A block of weight 12 N is suspended from the pair of springs, as shown above. When the block is in equilibrium, each spring is stretched an additional 24 cm. Thus, the equivalent spring constant of the two-spring system is 12 N / 24 cm = and k₂?

• k₁ = k₂ = 0.25 N/cm
• 1/k₁ + 1/k₂ = 1/(0.5 N/cm
• k₁ – k₂ = 0.5 N/cm
• k₁ + k₂ = 0.5 N/cm

A student pulls a wooden box along a rough horizontal floor at constant speed by means of a force P as shown to the right. Which of the following must be true?

• P > f and N < W.
• P > f and N = W.
• P = f and N > W.
• P = f and N = W.

Tags

NGSS.HS-PS2-1

The 10.0 kg box shown in the figure to the right is sliding to the right along the floor. A horizontal force of 10.0 N is being applied to the right. The coefficient of kinetic friction between the box and the floor is 0.20. The box is moving with:

•  acceleration to the left.
•  acceleration to the right.
•  constant speed and constant velocity
• constant speed but not constant velocity

Tags

NGSS.HS-PS2-1