Acceleration

A car with a mass of 1,200 kg experiences a net force of 3,600 N while moving along a highway.

• Identify the data and determine the car’s acceleration.

Answer explanation

Given mass (m) = 1200 kg and net force (F) = 3600 N. Use Newton's second law: F = m * a. Rearranging gives a = F/m = 3600 N / 1200 kg = 3 m/s². The car's acceleration is 3 m/s².

Tags

NGSS.MS-PS2-2

If an object has negative acceleration, it means...

• The velocity is increasing

• The velocity is decreasing

• The velocity is constant

• The object is stationary

Answer explanation

Negative acceleration indicates that the object is slowing down, meaning its velocity is decreasing. Therefore, the correct choice is that the velocity is decreasing.

Acceleration only takes place when things speed up. 

• True

• False

Answer explanation

False is correct because acceleration refers to any change in velocity, which includes speeding up, slowing down, or changing direction.

You are walking in a straight line at a consistent speed. Do you have acceleration? 

• no

• yes 

Answer explanation

When walking in a straight line at a consistent speed, your velocity is constant. Acceleration is defined as a change in velocity. Since there is no change in speed or direction, the correct answer is 'no'.

If an object is moving in a circle at a constant speed, is it accelerating?

• Yes

• No

Answer explanation

Yes, an object moving in a circle at a constant speed is accelerating because its direction is changing. Acceleration is defined as a change in velocity, which includes changes in direction.

What is the acceleration of a 50 kg object pushed with a force of 500 newtons?

• 100 m/s²

• 25,000 m/s²

• 10 m/s²

• 25 m/s²

Answer explanation

Using Newton's second law, F = ma, we can find acceleration (a) by rearranging the formula to a = F/m. Here, F = 500 N and m = 50 kg, so a = 500 N / 50 kg = 10 m/s². Thus, the correct answer is 10 m/s².

Tags

NGSS.MS-PS2-2

A student is doing an investigation using a 0.015 kg toy car. The student pushes the car with a force of 6 N, which causes the car to begin moving. What is the acceleration of the car when it begins to move?

• 0.0025 m/s2

• 200 m/s2

• 0.09 m/s2

• 400 m/s2

Answer explanation

Using Newton's second law, F = ma, we can find acceleration (a). Here, F = 6 N and m = 0.015 kg. Thus, a = F/m = 6 N / 0.015 kg = 400 m/s². Therefore, the correct answer is 400 m/s².

Tags

NGSS.MS-PS2-2

The rate at which velocity changes is called

• speed

• direction

• acceleration

• motion

A roller coasters accelerates from an initial velocity of of 6.0 m/s to a final velocity of 70 m/s over 4 seconds.  What's the acceleration?

• 24 m/s²

• 18 m/s²

• 16 m/s²

• 16 m/s

Tags

NGSS.HS-PS2-1

Changing the speed and changing the direction of your bicycle are both examples of acceleration.

• TRUE

• FALSE