Acceleration

What is the correct formula for acceleration?

• a = final velocity / time

• a = (final velocity - initial velocity) / change in time

• a = (initial velocity + final velocity) / time

• a = distance / time000

Answer explanation

The correct formula for acceleration is the change in velocity over time, which is the final velocity minus the initial velocity divided by the time interval.

In the formula for acceleration, what do the subscripts 'f' and 'i' stand for?

• final and infinite

• initial and infinite

• final and initial

• free and immediate

Answer explanation

In the acceleration formula, 'f' stands for final velocity, and 'i' stands for initial velocity, representing the velocities at the end and start of the motion, respectively.

Why is it important to carefully choose a direction as positive when calculating acceleration?

• It changes the speed of the object.

• It determines whether the acceleration is positive or negative.

• It affects the time variable in calculations.

• It ensures the correct direction of motion is assigned.

Answer explanation

Choosing a positive direction determines whether acceleration is labeled as positive or negative, affecting how the motion is interpreted.

What do many teachers incorrectly teach about positive acceleration?

• Positive acceleration always means the object is speeding up.

• Positive acceleration always means the object is slowing down.

• Positive acceleration means the object is moving backward.

• Positive acceleration means the object is stationary.

Answer explanation

Many incorrectly believe that positive acceleration always implies speeding up, but positive acceleration simply means the acceleration is in the chosen positive direction, regardless of whether the object speeds up or slows down

When does negative acceleration NOT mean slowing down?

• When the object is moving in the opposite direction of acceleration.

• When the object is moving in the same direction as the chosen negative direction.

• When the object has stopped.

• When the object is accelerating upward.

Answer explanation

When the object is moving in the same direction as the chosen negative direction.
Explanation: Negative acceleration doesn’t always mean slowing down; it depends on the direction chosen as positive or negative.

What is the proper meaning of negative acceleration?

• The object is always slowing down.

• The object is speeding up in the direction opposite to what was chosen as positive

• The object is moving backward.

• The object is coming to a stop.

Answer explanation

Negative acceleration doesn't necessarily mean the object is slowing down; it means the object is accelerating in the opposite direction of the positive direction chosen.

When you get a negative acceleration, what does it indicate about the object’s motion?

• The object is slowing down.

• The object is speeding up in the opposite direction to the chosen positive.

• The object is coming to a stop.

• The object is maintaining constant speed.

Answer explanation

Negative acceleration means the object is accelerating in the opposite direction to the positive, and it doesn’t always indicate that the object is slowing down.

If a car has an initial velocity of 12 m/s and a final velocity of 20 m/s over 4 seconds, what is its acceleration if right is chosen as positive?

• 2 m/s² to the left

• -2 m/s² to the right

• 2 m/s² to the right

• -2 m/s² to the left

Answer explanation

Using the formula a = (final velocity - initial velocity) / time, the acceleration is (20 - 12) / 4 = 2 m/s². Since right is chosen as positive, the acceleration is to the right.

What is the term used when an object is slowing down?

• Negative acceleration

• Deceleration

• Constant velocity

• Positive acceleration

Answer explanation

Deceleration is the term used to describe the process of an object slowing down.

In which direction will an object speed up if its motion and acceleration are in the same direction?

• The object will slow down.

• The object will speed up in the opposite direction.

• The object will speed up in the direction of motion.

• The object will stop.

Answer explanation

If the acceleration and motion are in the same direction, the object will speed up in that direction.