NW1 Review

Match the following symbols with their variable

• t

• time

• y

• horizontal displacement

• x

• velocity

• a

• acceleration

• v

• vertical displacement

Match the following variable with the unit it is measured in

• seconds

  (s)

• discplacement (x or y)

• meters

  (m)

• acceleration (a)

• meters/second

  (m/s)

• velocity (v)

• meters/second²

  (m/s²)

• time (t)

What is happening in this graph?

• Speeding up

• Slowing down

• Constant velocity

• At rest

Answer explanation

The graph shows a straight line with a constant slope, indicating that the object is moving at a constant velocity. There are no changes in speed or direction, confirming that it is not speeding up, slowing down, or at rest.

What is the velocity of the object? (hint: rise/run)

• 20 m/s

• 10 m/s

• 5 m/s

• 15 m/s

Answer explanation

To find the velocity, use the rise/run method. If the rise is 5 meters and the run is 1 second, the velocity is 5 m/s. Thus, the correct answer is 5 m/s.

What is the acceleration of the object?

• 20 m/s²

• 10 m/s²

• 0 m/s²

• 5 m/s²

Answer explanation

The acceleration of the object is 0 m/s², indicating that it is at rest or moving at a constant velocity with no net force acting on it.

Tags

NGSS.HS-PS2-1

A train is moving 120 km/hr east. Javier is walking 5 km/hr relative to the train. Kassandra is moving to the back of the train (opposite direction) at 7 km/hr. From Kassandra's frame of reference, how fast is Javier moving?

• 127 km/hr

• 12 km/hr

• 125 km/hr

• 2 km/hr

• 1.28 s

• 1.27 s

• 1.38 s

• 1.18 s

Answer explanation

Using the formula y = v_i t + (1/2)gt^2, with y = 8 m, v_i = 0, and g = 9.81 m/s², we solve for t. This gives t ≈ 1.28 s, confirming the correct answer is 1.28 s.

The graph abpve represents the motion of a cyclist. The graph shows that the cyclist was always

• speeding up

• slowing down

• going the same direction

• changing direction and speed

Tags

NGSS.HS-PS2-1

How much force is needed to accelerate a 1500kg car at a rate of 1.8 m/s²?

• 1200 N

• 2700 N

• 8493 N

• 16,562 N

Answer explanation

To find the force needed, use Newton's second law: F = m * a. Here, m = 1500 kg and a = 1.8 m/s². Thus, F = 1500 * 1.8 = 2700 N. Therefore, the correct answer is 2700 N.

Tags

NGSS.HS-PS2-1

A basketball, soccer ball, and football were kicked. Which of these statements is the best example of Newton's First Law of Motion in this situation?

• The ball with the least resistance gained the most speed.

• Each ball rolled to a stop due to the unbalanced force of friction

• Each ball exerted an equal force on the person's foot

• The ball kicked with the least force traveled the greatest distance.

Answer explanation

The correct statement illustrates Newton's First Law, as it shows that each ball continues in motion until acted upon by an unbalanced force, like friction, which eventually brings them to a stop.