5.2 Representations of Changes in Momentum

A cart of mass 1kg travels along a horizontal, frictionless surface. A net force is applied to the cart. A graph of the net force applied to the cart as a function of time is shown. The initial and final direction of the cart and the direction of the net force exerted on the cart is unknown. The distance of one grid unit represents a change in velocity of 1 m/s. Which of the following diagrams could represent the direction and relative magnitude of the velocity of the cart before the force is applied and after the force is applied? Select two answers.

• 
• 
• 
• 

Tags

NGSS.HS-PS2-1

A 2kg object travels in the positive direction across a horizontal surface with a constant speed of 10ms . A force is exerted on the object for 4s, and the force increases linearly with respect to time. The table shows data about the magnitude of the applied force exerted on the object at different times. The force is exerted on the object in the opposite direction of the object’s displacement. What is the change in momentum of the object?

• 8N⋅s in the positive direction

• 8N⋅s in the negative direction

• 16N⋅s in the positive direction

• 16N⋅s in the negative direction

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

A force probe is used to push a box across a smooth surface, as shown in the figure. Frictional forces are considered to be negligible. The force probe collects data about the force exerted on the box as a function of time. The data are used to create the graph that is shown. During which time interval does the box experience the greatest change in its momentum?

• 0 to 2 s

• 2 to 4 s

• 4 to 6 s

• The change in momentum is the same for each interval of time.

Tags

NGSS.HS-PS2-1

A 2kg object travels across a horizontal surface with a constant speed of 6m/s. An applied force that increases with time is then exerted on the object. A graph of the force exerted on the object as a function of time is shown. The applied force is in the direction of the object’s displacement. All frictional forces are considered to be negligible. What is the object’s speed after the force has been applied for 4s?

• 16 m/s

• 22 m/s

• 32 m/s

• 44 m/s

Tags

NGSS.HS-PS2-1

Two identical spheres of known mass M are attached to opposite ends of a rod of negligible mass. The mass-rod-mass system is spun in the vertical plane and then released so the system falls downward as it rotates, as shown in the figure. Data are collected and shown in the graph of the vertical velocity, v, of the two spheres as a function of time t. The positive direction is considered to be downward. A student uses the graph to make three claims.

Claim 1: Change in linear momentum of the center of mass of the system from 0.0s to 0.5s can be determined.

Claim 2: The average applied force exerted on the center of mass of the system from 0.0s to 0.5s can be determined.

Claim 3: The change in the kinetic energy of the system from 0.0s to 0.5s can be determined.

Which of the student's claims are correct?

• Claim 1 and 2 only

• Claim 1 and 3 only

• Claim 2 and 3 only

• All claims

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

In an experiment, a variable net force is applied to an object. A graph of the net force exerted on the object as a function of time is shown. Which of the following experiments could have been conducted to represent the variable net force shown in the graph?

• A 0.2kg object increases its speed from 2m/s to 8m/s .

• A 1kg object increases its speed from 2m/s to 4m/s .

• A 2kg object increases its speed from 1m/s to 3m/s .

• A 3kg object increases its speed from 0m/s to 1m/s .

Tags

NGSS.HS-PS2-1