Newton's Laws
This law states that an object at rest stays at rest, and an object in motion stays in motion unless acted upon by an unbalanced force.
What is Newton's First Law (or Law of Inertia)?
Forces that require two physical objects to touch each other are classified under this broad group.
What are contact forces?
In a free-body diagram, an object is typically represented as a dot or box, and forces are drawn using these items extending outward.
What are vector arrows?
True or False: The universal gravitational constant (G) is the exact same value as Earth's gravitational acceleration (g = 9.8 m/s2).
What is False?
What room number is this physics class held in?
What is room 30
Between a 0.15 kg baseball and a 5 kg bowling ball, this object has greater inertia.
What is the bowling ball (because inertia depends directly on mass)?
This supportive contact force is exerted perpendicular to a surface holding up an object at rest.
What is the Normal force (FN)?
An object moves at a constant velocity of 15 m/s to the right. The net force acting on the object is equal to this value.
What is 0 N (balanced forces/equilibrium)?
If you double the distance between two masses, the gravitational force between them decreases by this factor.
What is 1/4 (or four times weaker, due to inverse-square law)?
If you drop a 5 kg steel bowling ball and a 1 kg rubber ball from the top of a building inside a complete vacuum, which hits the ground first?
What is they hit at the exact same time? (In a vacuum, all objects fall with the same gravitational acceleration regardless of mass.)
A net force of 50 N acts on a 10 kg sled. This is the acceleration experienced by the sled.
What is 5 m/s2 (a = F/m = 50/10)
This force is transmitted through a pulled cable, rope, or string.
What is Tension (FT)?
A box experiences a 25 N force pushing it right and a 10 N friction force pulling left. State the horizontal net force (magnitude and direction).
What is 15 N to the right?
When calculating gravitational force using Fg = G (m1 m2)/d2, distance (d) must be measured between these two points on the objects.
What are the centers of mass of the two objects?
Which weighs more: 100 kg of feathers or 100 kg of iron bricks?
What is neither / they weigh the same? (Both have a mass of 100 kg.)
When a rocket engine expels hot gas downward, the rocket accelerates upward. This action-reaction pair illustrates which law?
What is Newton's Third Law?
The resistive fluid drag force felt by an object moving through air, such as a falling skydiver.
What is air resistance (or drag)?
An object experiences 12 N up, 12 N down, 30 N right, and 8 N left. State the net force vector components (Fnet, x and Fnet, y).
What is Fnet, x = 22 N right and Fnet, y = 0 N?
Two spherical lead balls (10 kg and 20 kg) are placed 1 m apart. Calculate the force of gravitational attraction between them using G = 6.67 x 10^-11 Nm2/kg2.
What is 1.33 10-9 N?
A force of 120 N accelerates an object at 4 m/s2. If the mass is halved and the force is doubled, calculate the new acceleration.
What is 16 m/s2? (Original mass = 30 kg; new mass = 15 kg, new force = 240 N; a = 240/15)
Contrast mass and weight by explaining which one changes when taking an object to the Moon and why.
What is weight (or force of gravity, Fg), because weight depends on gravitational field acceleration (g), while mass remains constant?
A crate is pulled across a floor. The upward normal force is 80 N, the applied force right is 60 N, and the net force is 20 N right. Calculate the force of gravity (Fg) and the friction force (Ff).
What are Fg = 80 N (downward equilibrium) and Ff = 40 N (60 N - 20 N)?
If the mass of Object A is doubled, and the mass of Object B is tripled, by what total factor does the gravitational force between them increase?
What is 6 times?