Unit 2 Forces and Collisions Review

Match the units with their term.

Groups:

(a) Speed

,

(b) Velocity

,

(c) Acceleration

• m/s west

• m/s

• mi/hr north

• km/hr

• m/s^2

• km/min^2

Answer explanation

Speeds are distance per unit time.

Velocities are speeds with a direction, so look for the direction with the units!

Accelerations have the time unit squared (either like m/s² or m/s^2. Sometimes programs won't let us do the exponent so we have to use the ^ to show the exponent.

Tags

NGSS.MS-PS3-1

The segment label with the description.

• the person stopped

• Segment C

• the person traveled 30 km in 2 hrs

• Segment B

• returned to starting location

• Segment D

• fastest speed (30 km in 30 min)

• Segment A

Tags

NGSS.MS-PS3-1

What was the speed of the object in Segment C?

• 30 min

• 30 km

• 1 km / min

• 0 km / hr

• 2 km / min

Tags

NGSS.MS-PS3-1

Match the time frame with the object's motion descriptions.

• the object slowed down until it stopped

• 30 - 45 s

• the object sped up from a stop

• 10 - 30 s

• maintained a constant speed (not 0)

• 0 - 10 s

Tags

NGSS.MS-PS3-1

The force of a cart doubles.  What happens to the cart's acceleration?

• It doubles
• It quadruples 
• It halves
• It quarters

Tags

NGSS.MS-PS2-2

If a 10 kilogram object accelerates suddenly at 15 m/s², how much force was applied to the object?

• 150 Newtons

• 15 Newtons

• 150 kilograms

• 100 kilograms

Tags

NGSS.MS-PS2-2

A 240N unbalanced force applied to push a chair across the room causing an acceleration of 4 m/s². What is the mass of the chair?

• 60 kg

• 80 kg

• 986 kg

• 40 kg

Tags

NGSS.MS-PS2-2

The force on an object is cut in half and the mass stays the same. What happens to the acceleration?

• The acceleration remains constant.

• The acceleration is cut in half.

• The acceleration doubles.

Answer explanation

The mass of the object stays the same but we are pushing on it with less force. This means it will move slower, so the acceleration has to decrease.

Example: Mass is 1 kg and force is 4 N. Acceleration is 4 N / 1 kg = 4 m/s².

Now mass is still 1 kg and the force is reduced to 2 N. Acceleration is 2 N / 1 kg = 2 m/s².

So the acceleration is cut in half.

Tags

NGSS.MS-PS2-2

The force on an object is doubled and the mass is doubled. What happens to the acceleration?

• The acceleration remains constant.

• The acceleration is cut in half.

• The acceleration doubles.

Answer explanation

Since both the force and mass are doubled, the larger object will accelerate at the same rate as the smaller object.

Example: Mass is 1 kg and force is 2 N. Acceleration is 2 N / 1 kg = 2 m/s².

Now mass is doubled to 2 kg and the force is doubled to 4 N. Acceleration is 4 N / 2 kg = 2 m/s².

So the acceleration stays at 2 m/s².

Tags

NGSS.MS-PS2-2

Earth's gravity is ​ ​ (a)   ​ m/s2.​ ​

• 9.8
• 12
• 1,000
• 8.809

Tags

NGSS.5-PS2-1