A constant 15-newton force, F, is applied to a 2.5-kilogram box. The box is accelerating to the right at 2.0 m/s² across a rough horizontal surface. What is the force of friction on the box?

• 2 N

• 5 N

• 10 N

• 15 N

Tags

NGSS.HS-PS2-1

The Doppler effect is best described as the

• bending of waves as they pass by obstacles or through openings

• change in speed of a wave as the wave moves from one medium to another

• creation of a standing wave from two waves traveling in opposite directions in the same medium

• shift in the observed frequency and wavelength of a wave caused by the relative motion between the wave’s source and an observer

Tags

NGSS.HS-PS4-1

Students are creating standing waves on a string with a wave generator. They start with a very low frequency (1 Hz) and slowly increase the frequency and record the frequency of each standing wave. One of the standing waves they create is shown below. How many antinodes are shown in this standing wave?

• 1

• 2

• 3

• 4

Tags

NGSS.HS-PS4-1

Students are creating standing waves on a string with a wave generator. They start with a very low frequency (1 Hz) and slowly increase the frequency and record the frequency of each standing wave. One of the standing waves they create is shown below. How many standing waves will the students find before they discover the one pictured above?

• 0

• 1

• 2

• 3

Tags

NGSS.HS-PS4-1

A student is standing in an elevator that travels from the first floor to the tenth floor of a building. The student exerts the greatest force on the floor of the elevator when the elevator is

• accelerating upward as it leaves the first floor

• slowing down as it approaches the tenth floor

• moving upward at constant speed

• at rest on the first floor

Tags

NGSS.HS-PS2-1

A graph of the net horizontal force F exerted on an object as a function of x position is shown for the object of mass M as it travels a horizontal distance of 6.0 m. What is the change in kinetic energy of this object over this distance?

• 60 J

• 70 J

• 80 J

• 90 J

Tags

NGSS.HS-PS2-1

NGSS.HS-PS3-1

The graph below represents the relationship between velocity and time for an object moving along a straight line. What is the magnitude of the object's acceleration?

• 5.0 m/s²

• 8.0 m/s²

• 10.0 m/s²

• 20.0 m/s²

Tags

NGSS.HS-PS2-1

In addition to the data in the graph above, what else would students need to measure to determine the magnitude of the net force on this object?

• Mass only

• Distance the object travels each second

• The direction of the motion

• The mass of the object and the distance it travels each second

Tags

NGSS.HS-PS2-1

A projectile is launched from the ground and lands at the same height from which it was launched. For which initial velocity will the projectile be in the air the longest? [Neglect friction.]

• v_i = 20 m/s at 60°

• v_i = 20 m/s at 45°

• v_i = 10 m/s at 45°

• v_i = 10 m/s at 30°

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

A 5.0-kilogram box is sliding across a level floor. The box is acted upon by a force of 25 newtons east and a frictional force of 15 newtons west. What is the magnitude of the acceleration of the box?

• 0.50 m/s²

• 2.0 m/s²

• 3.0 m/s²

• 5.0 m/s²

Tags

NGSS.HS-PS2-1