Linear Momentum

A car of mass m, traveling at speed v, stops in time t when maximum braking force is applied. Assuming the braking force is independent of mass, what time would be required to stop a car of mass 2m traveling at speed v?

• ½t
• t
• √2 t
• 2t

Tags

NGSS.HS-PS2-1

Two objects, P and Q, have the same momentum. Q can have more kinetic energy than P if it has:

• More mass than P 
• The same mass as P 
• More speed than P 
• The same speed as P 

Tags

NGSS.HS-PS2-2

A spring is compressed between two objects with unequal masses, m and M, and held together. The objects are initially at rest on a horizontal frictionless surface. When released, which of the following is true?

• The total final kinetic energy is zero.
• The two objects have equal kinetic energy.
• The speed of one object is equal to the speed of the other.
• The total final momentum of the two objects is zero.

Tags

NGSS.HS-PS2-2

Two football players with mass 75 kg and 100 kg run directly toward each other with speeds of 6 m/s and 8 m/s respectively. If they grab each other as they collide, the combined speed of the two players just after the collision would be:

• 2 m/s 
• 3.4 m/s 
• 4.6 m/s 
• 7.1 m/s

Tags

NGSS.HS-PS2-2

A 5000 kg freight car moving at 4 km/hr collides and couples with an 8000 kg freight car which is initially at rest. The approximate common final speed of these two cars is

• 1 km/h 
• 1.3 km/h 
• 1.5 km/h 
• 2.5 km/h

Tags

NGSS.HS-PS2-2

Two pucks are firmly attached by a stretched spring and are held at rest on a frictionless surface. They are released simultaneously. If puck I has 3X the mass of puck II, which of the quantities is the same for both as the spring pulls the two pucks?

• Speed 
• Magnitude of acceleration 
• Kinetic energy 
• Magnitude of momentum

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

Which of the following is true when an object of mass m moving on a horizontal frictionless surface hits and sticks to an object of mass M > m, which is initially at rest on the surface?

• The collision is elastic.
• The momentum of the objects that are stuck together is smaller than the initial momentum of object m.
• The speed of the objects that are stuck together will be less than the initial speed.
• The direction of motion of the objects that are stuck together depends on whether the hit is a head-on collision.

Tags

NGSS.HS-PS2-2

Two objects having the same mass travel toward each other on a flat surface each with a speed of 1.0 meter per second relative to the surface. The objects collide head-on and are reported to rebound after the collision, each with a speed of 2.0 meters per second relative to the surface. Which of the following assessments of this report is most accurate?

• Momentum was not conserved therefore the report is false.
• If potential energy was released to the objects during the collision the report could be true.
• If the objects had different masses the report could be true.
• If the surface was inclined the report could be true.

Tags

NGSS.HS-PS2-2

An open cart on a level surface is rolling without frictional loss through a vertical downpour of rain. As the cart rolls, an appreciable amount of rainwater accumulates in the cart. The speed of the cart will

• increase because of conservation of mechanical energy
• decrease because of conservation of momentum
• decrease because of conservation of mechanical energy
• remain the same because the raindrops are falling perpendicular to the direction of the cart's motion

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

A student obtains data on the magnitude of force applied to an object as a function of time and displays the data on the graph shown. The increase in the momentum of the object between t=0 s and t=4 s is most nearly

• 40 N·s
• 50 N·s
• 60 N·s
• 80 N·s

Tags

NGSS.HS-PS2-1