P5.12 Calculations of motion

What is the definition of "mass"?

• The force of gravity on an object.

• The quantity of matter in an object.

• The size of an object.

What is the definition of "weight"?

• The quantity of matter in an object.

• The force of gravity acting on an object.

• The resistance to acceleration.

How does the Earth's gravitational field strength vary from the equator to the poles?

• It is stronger at the equator.

• It is stronger at the poles.

• It is the same everywhere.

What is "free fall"?

• When an object is moving upwards.

• When an object falls under the influence of gravity alone, with negligible air resistance.

• When an object is thrown horizontally.

What happens to the acceleration of an object as it falls through a fluid (e.g., air or liquid)?

• It increases steadily.

• It decreases as air resistance increases.

• It remains constant.

What is "terminal velocity"?

• The maximum speed an object can reach before it breaks apart.

• The constant velocity reached by a falling object when the resultant force on it is zero.

• The initial velocity of a falling object.

When does an object reach terminal velocity?

• When its weight is greater than the air resistance.

• When its weight is equal to the air resistance.

• When its acceleration is at its maximum.

What is the approximate value of the Earth's gravitational field strength?

• 1 N/kg.

• 9.8 N/kg.

• 100 N/kg.

What are the two forces acting on a falling object that determine its terminal velocity?

• Mass and volume.

• Weight and air resistance (or drag force).

• Gravity and buoyancy.

If an object is moving at a constant velocity in a fluid, what can be said about the resultant force acting on it?

• It is increasing.

• It is decreasing.

• It is zero.