Definitions
Gravitational Force: The force of attraction between two masses due to their mass and distance apart. It is described by Newton's law of universal gravitation.
Weight: The force exerted on an object due to gravity. It is calculated as the mass of the object multiplied by the acceleration due to gravity (Weight = Mass × Gravity).
Mass: A measure of the amount of matter in an object, typically measured in kilograms (kg). Mass does not change regardless of location.
Gravitational Attraction: The attractive force exerted by one mass on another due to gravity, influencing how strongly objects pull toward each other.
Mass vs. Weight
How are mass and weight different? Mass is a measure of how much matter is in an object and remains constant regardless of location. Weight, however, is the force that gravity exerts on that mass and can vary depending on the local gravitational field strength.
Gravity on Different Vehicles
Would the force of gravity be the same or different on a compact car and a large tractor trailer? The force of gravity acting on each vehicle will be different because gravity depends on mass. The larger tractor trailer, having more mass, will experience a greater gravitational force.
Weight on Mars vs. Earth
Would a person’s weight be the same or different on Mars as it is on Earth? What about his/her mass? A person’s weight would be different on Mars due to the weaker gravitational pull (about 38% of Earth's gravity). However, their mass would remain the same because mass is constant regardless of location.
Comparing Weights of Objects
Which object would feel heavier on Earth: a single apple or a bag of apples? A bag of apples would feel heavier on Earth because it contains more mass and therefore has a greater weight.
Gravitational Attraction on the Moon
Why is gravitational attraction less on the moon than it is on Earth? The gravitational attraction is less on the Moon because it has significantly less mass than Earth, leading to a weaker gravitational pull.
Investigating Gravity
Define:
Acceleration: The rate of change of velocity of an object. It can be caused by the force acting on it.
Gravity: A natural phenomenon by which all things with mass or energy are brought toward one another, essential for keeping planets in orbit and driving the motion of falling objects.
What happens when dropping balls of varying mass? If you drop a foam ball, a soccer ball, and a bowling ball from the same height, they will all reach the Earth at the same time, assuming no air resistance.
What does this tell us about the force of gravity on objects with different masses? This indicates that the force of gravity accelerates all objects at the same rate, regardless of their mass.
The acceleration due to gravity is the (same) for objects with different masses. (Highlight the correct answer)
Analyzing Gravitational Data
Define Air Resistance: The frictional force air exerts against a moving object, which opposes the motion.
Air resistance acts opposite of what force? Air resistance acts opposite to the force of gravity.
If you drop a feather and a bowling ball from the same height (without air resistance), would they reach the ground at the same time? Yes, without air resistance, they would reach the ground at the same time.
Why do a feather and a bowling ball not hit the ground at the same time when dropped from the same height? In the presence of air resistance, the feather encounters much more drag relative to its weight, causing it to fall more slowly than the bowling ball.
Gravity and Air Resistance
Define Terminal Velocity: The constant speed that a freely falling object eventually reaches when the resistance of the medium (like air) prevents further acceleration.
What term means that the force of air resistance equals the force of gravity? Terminal velocity is reached when the forces of air resistance and gravity are equal, resulting in no net force and constant velocity.
What happens when a skydiver opens his parachute? When a skydiver opens his parachute, the force of air resistance increases significantly, which opposes the force of gravity, causing the skydiver to decelerate and eventually reach a lower terminal velocity.