week 3 Flashcards
What is Newton’s Law of Gravitation?
Every particle in the universe attracts every other particle with an attractive force: F = G m1 m2/r²
Where G is the universal constant (6.67 x 10⁻¹¹), m1 and m2 are the masses of the two objects, and r is the distance between them.
What does the equation F = G m1 m2/r² imply about distance and attractive force?
The longer the distance (r) between two objects, the smaller the attractive force (F).
What is the value of the universal constant G?
6.67 x 10⁻¹¹
Calculate the force between two cricket balls (mass=158g) 5m apart using Newton’s Law of Gravitation.
F = 6.67 x 10⁻¹¹ x 0.158 x 0.158 / 5² = 6.67 x 10⁻¹⁴ N.
What is Newton’s 3rd Law?
For every action, there is an equal and opposite reaction.
What does Newton’s 3rd Law imply about forces?
For every force exerted by one body on another, there is an equal and opposite force exerted by the second body on the first.
True or False: Equal and opposite forces always cancel each other out.
False.
What is the formula for Newton’s 2nd Law?
F = ma
What does Newton’s 2nd Law state about acceleration?
The rate of change of motion (acceleration) of a body is proportional to the force acting on it and is in the direction that the force acts.
What is 1 Newton (N)?
The amount of force necessary to accelerate a mass of 1 kg at 1 m/sec².
What happens to a body at rest or moving with constant velocity according to Newton’s 1st Law?
A body at rest will stay at rest, and a body moving with constant velocity will keep moving with constant velocity if the net external force is 0.
What does the Law of Inertia state?
If no external forces are applied on a body, or if the net sum of any applied external forces is zero, then the body’s motion remains unchanged.
What is the formula for weight (W) of an object?
W = mg
What is the effective gravitational acceleration on the surface of the Earth?
g = 9.81 m/sec²
Fill in the blank: Mass is ______ the same as weight.
not
What is inertia in linear motion?
The resistance of a body to changes in its motion, measured by its mass.
What is the relationship between mass and inertia?
The more massive a body, the greater its inertia.
What does the center of gravity (CG) represent?
The point where all of a body’s mass is considered to be concentrated for the purposes of analyzing motion.
Does the center of gravity need to lie within the physical limits of the body?
No.
What would an 80kg person weigh on the moon, where gravity is 1.57 m/s²?
Weight on moon = 80 kg x 1.57 m/s² = 125.6 N.
What is the difference between weight and mass?
Weight is the force acting on a body due to gravity, while mass is the quantity of matter in a body.
What is the formula for calculating weight based on gravity and mass?
W = mg
What are the three laws formulated by Newton?
- 1st Law - Law of Inertia
- 2nd Law - Law of Acceleration
- 3rd Law - Law of Action-Reaction
What is the significance of Newton’s laws in biomechanics?
They are fundamental to understanding the movements of the human body and sports equipment.
Who was Sir Isaac Newton?
An English physicist and mathematician (1642-1727).
