Science 7 (3rd Qtr - review)

Which of the following is a scalar quantity?

• displacement

• distance

• acceleration

• velocity

Answer explanation

Distance is a scalar quantity as it only has magnitude and no direction. In contrast, displacement, acceleration, and velocity are vector quantities, which include both magnitude and direction.

Which of the following is vector quantity?

• displacement

• distance

• speed

• time

Answer explanation

Displacement is a vector quantity as it has both magnitude and direction, representing the shortest path from one point to another. In contrast, distance, speed, and time are scalar quantities, lacking direction.

Which of the following quantities shows displacement?

• 4 m/s

• 5 m/s²

• 40 m/s north

• 40 m east

Answer explanation

Displacement is a vector quantity that includes direction. '40 m east' indicates both distance and direction, making it the correct choice. The other options represent speed or acceleration, not displacement.

Which of the following quantities shows velocity?

• 4 m/s

• 5 m/s²

• 40 m/s north

• 40 m east

Answer explanation

Velocity is a vector quantity that includes both speed and direction. '40 m/s north' specifies a speed of 40 meters per second in a specific direction (north), making it the only option that shows velocity.

Which of the following may happen on particles when an object when temperature decreases?

• Slow down until stop

• Be released towards the environment

• Continuously moving until it achieves thermal equilibrium

• Nothing happens

Answer explanation

As temperature decreases, particles lose energy and slow down, potentially coming to a stop. This aligns with the correct choice, 'Slow down until stop', as lower temperatures reduce particle motion.

How much would be the mass of an object that has a weight of 97 N?

• 9.90 kg

• 87 kg

• 0.10 kg

• 950.6 kg

Answer explanation

To find the mass from weight, use the formula: weight = mass × gravity. Here, weight = 97 N and gravity ≈ 9.81 m/s². Thus, mass = 97 N / 9.81 m/s² ≈ 9.90 kg, making 9.90 kg the correct answer.

How much time would it take for a tourist bus to reach its destination, 5.75 kilometers away from its terminal at a speed of 60 km/h?

• 65.75 hours

• 0.09 hour

• 10.44 hours

• 54.25 hours

Answer explanation

To find the time, use the formula: time = distance/speed. Here, time = 5.75 km / 60 km/h = 0.0958 hours, which rounds to 0.09 hours. Thus, the correct answer is 0.09 hour.

What would be the weight of a 21-kg object standing on Earth?

• 30.8 N

• 11.2 N

• 2.14 N

• 205.8 N

Answer explanation

The weight of an object is calculated using the formula: weight = mass × gravity. On Earth, gravity is approximately 9.81 m/s². Thus, for a 21-kg object: 21 kg × 9.81 m/s² = 205.8 N, making 205.8 N the correct answer.

Which of the following distance-time graph represents uniform acceleration with increasing speed?

• 
• 
• 
• 

Which is a unit of speed?

• m

• km

• km/h

• s/m

Answer explanation

The correct unit of speed is km/h, which indicates kilometers traveled per hour. The other options (m, km, s/m) do not represent speed; m and km are units of distance, while s/m is a ratio of time to distance.