50+ Science worksheets for 9th Class on Quizizz | Free & Printable - Free Printable

Let's solve each problem step by step:

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Problem 1:

Question: You buy an extra-large Coke at QT and forget to put the lid on. A car pulls out in front of you, and your mom yells, “Look out!” You hold your cup still so it won’t spill. However, the Coke still spills out. Which term explains this situation?

- A. density
- B. gravity
- C. inertia
- D. friction

Explanation:
When the car pulls out in front of you, you suddenly stop or slow down. The liquid in the cup (Coke) continues to move forward because of its inertia. Inertia is the tendency of an object to resist changes in its state of motion. This is why the Coke spills out even though you are holding the cup still.

Answer: C. inertia

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Problem 2:

Question: A train was going down the track and a curve was approaching. The conductor went to apply the brake but they did not work. What can account for the train eventually slowing down even though there were no brakes?

- A. The natural state of the train is not to be in motion.
- B. The opposing force of friction stopped the train.
- C. The train ran out of momentum.
- D. The force of gravity slowed the train until it stopped.

Explanation:
Even without brakes, the train will eventually slow down due to friction. Friction between the train wheels and the tracks, as well as air resistance, acts as an opposing force that gradually reduces the train's speed until it stops.

Answer: B. The opposing force of friction stopped the train.

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Problem 3:

Question: What is the acceleration difference between Car 1 and Car 2?

The graph shows:
- Car 1: A straight line with a positive slope.
- Car 2: A curved line that starts steep and then levels off.

Options:
- A. Car 1 changes velocity and Car 2 increases and decreases its speed.
- B. Car 1 stays constant and Car 2 changes its speed during the trip.
- C. Car 2 stays constant and Car 1 changes its speed during the trip.
- D. Car 1 starts & stops and Car 2 stays constant.

Explanation:
- Car 1: The graph shows a straight line with a constant slope. This indicates that Car 1 has a constant acceleration (or constant velocity if the slope is zero).
- Car 2: The graph shows a curved line that starts steep and then levels off. This indicates that Car 2 has a changing acceleration (it accelerates quickly at first and then slows down).

Thus, Car 1 has constant acceleration, while Car 2 has changing acceleration.

Answer: B. Car 1 stays constant and Car 2 changes its speed during the trip.

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Problem 4:

Question: Two PE classes are playing tug of war in gym class today. Which factor is most important in determining who will win excluding the number of players on each team?

- A. The temperature outside
- B. The length of the rope
- C. The surface of the floor
- D. The total mass of the team

Explanation:
In tug of war, the primary factor determining the winner is the total force applied by each team. The total force is directly related to the mass of the team and the effort (force) they can exert. While other factors like the surface of the floor (friction) can play a role, the most significant factor is the total mass of the team, as more mass generally means more force can be applied.

Answer: D. The total mass of the team

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Problem 5:

Question: Which baseball would have more acceleration with the same amount of force?

The image shows three baseballs:
1. A standard baseball.
2. A lighter baseball.
3. A heavier baseball.

Explanation:
According to Newton's Second Law of Motion, \( F = ma \), where:
- \( F \) is the force applied,
- \( m \) is the mass of the object,
- \( a \) is the acceleration.

Rearranging the equation gives:
\[ a = \frac{F}{m} \]

This means that for the same force \( F \), the acceleration \( a \) is inversely proportional to the mass \( m \). Therefore, the lighter baseball will have more acceleration because it has less mass.

Answer: The lighter baseball will have more acceleration.

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Final Answers:

1. C. inertia
2. B. The opposing force of friction stopped the train.
3. B. Car 1 stays constant and Car 2 changes its speed during the trip.
4. D. The total mass of the team
5. The lighter baseball

Boxed Final Answer:
\[
\boxed{C, B, B, D, \text{The lighter baseball}}
\]