REview Part 1

What is the SI unit for speed?

• m/s

• m/s²

• kg

• N

Answer explanation

The SI unit for speed is meters per second (m/s). It measures the distance traveled in meters for each second of time, making it the correct choice compared to other options like m/s² (acceleration) or kg (mass).

Tags

NGSS.MS-PS3-1

Speed is calculated as:

• Mass + Time

• Distance ÷ Time

• Force × Time

• Acceleration × Mass

Answer explanation

Speed is defined as the distance traveled divided by the time taken. Therefore, the correct formula for calculating speed is Distance ÷ Time.

Tags

NGSS.MS-PS3-1

What is the SI unit of force?

• Newton

• Joule

• Watt

• Meter

Answer explanation

The SI unit of force is the Newton, named after Sir Isaac Newton. It is defined as the force required to accelerate a one-kilogram mass by one meter per second squared.

Which of the following is a vector quantity?

• Distance

• Speed

• Displacement

• Time

Answer explanation

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

What force pulls objects toward Earth?

• Magnetic

• Friction

• Gravity

Answer explanation

The force that pulls objects toward Earth is gravity. It is a natural phenomenon that attracts two bodies with mass towards each other, and in this case, it pulls everything towards the center of the Earth.

Tags

NGSS.5-PS2-1

Velocity is speed with:

• Direction

• Force

• Time

• Power

Answer explanation

Velocity is defined as speed with direction. Unlike speed, which is a scalar quantity, velocity is a vector quantity that includes both magnitude and direction, making 'Direction' the correct choice.

Distance can be less than displacement.

• True

• False

Answer explanation

Displacement is the shortest distance between two points, while distance is the total path traveled. Therefore, distance cannot be less than displacement, making the statement false.

Which device is used to measure time in experiments?

• Thermometer

• Stopwatch

• Spring balance

• Barometer

Answer explanation

The stopwatch is specifically designed to measure time intervals, making it the correct choice for experiments that require precise timing. Other devices like thermometers and barometers measure temperature and pressure, respectively.

Acceleration is a change in:

• Distance

• Time

• Velocity

• Mass

Answer explanation

Acceleration refers to the rate of change of velocity over time. It indicates how quickly an object's speed or direction is changing, making 'velocity' the correct choice.

Tags

NGSS.MS-PS2-2

Which force resists motion between surfaces?

• Gravity

• Normal force

• Friction

• Magnetic force

Answer explanation

Friction is the force that opposes the relative motion of two surfaces in contact. It acts parallel to the surfaces and is responsible for resisting sliding or rolling motion, making it the correct answer.