Forces
These are the two types of friction.
What are static and kinetic?
Centripetal acceleration and centripetal force always point in this direction relative to the circular path.
What is towards the center?
This is the type of stored energy related to changes in elevation.
What is gravitational potential energy?
The work done by a conservative force, such as gravity, around any closed loop path where an object returns to its starting position is always equal to this.
What is zero?
Linear momentum is calculated as the product of an object's mass and this vector quantity
What is velocity?
This type of friction acts on objects that are actively sliding across a surface.
What is kinetic?
This is the formula for centripetal acceleration in terms of tangential speed v and radius r.
What is v2/r?
The Work-Energy Theorem states that the net work done on an object is equal to the change in this specific type of energy.
What is kinetic energy?
If you push against a heavy concrete wall with a force of 500 N for 10 seconds and it does not move, this is the amount of work you have done.
What is zero?
Airbags in modern cars protect passengers during a crash primarily by extending this variable over a longer period, which drastically reduces peak impact force.
What is time?
When you walk forward across a flat floor, the directional force of static friction acting on your shoes from the ground actually points in this direction.
What is forward? (Your foot pushes backward against the ground, so the ground exerts a forward frictional force on you)
When a car rounds a flat, unbanked curve on a highway, this specific force provides the necessary centripetal force.
What is friction?
An ideal spring with spring constant k is stretched by a distance x. This is the formula for its stored elastic potential energy.
What is Us=1/2kx2?
A constant force vector F = (3i + 4j) N displaces an object along a vector d = (2i - 5\j) m. This is the total work done by the force.
What is -14 Joules?
This specific type of collision conserves both total momentum and total kinetic energy.
What is elastic?
A 10 kg box rests on a horizontal surface. If the coefficient of kinetic friction is 0.30, what is the friction force while the box slides?
What is 29.4 N?
If an object's speed doubles while its circular path's radius stays the same, by what factor does its centripetal acceleration change?
What is four times as large?
A roller coaster starts from rest at a height of 20 m. Ignoring friction, how fast is it moving when it reaches a height of 5 m?
What is 17.1 m/s?
Friction exerts a 15 N force opposite the motion of a sliding box. If the box travels 8 m, how much work does friction do?
What is -120 J?
A stationary cannon fires a heavy cannonball forward. According to momentum conservation, the total momentum of the cannon-cannonball system immediately after firing remains equal to this value.
What is zero? (The forward motion of the ball is balanced by the recoil of the cannon)
A 20 kg crate is pulled horizontally with 100 N of force. The coefficient of kinetic friction is 0.25. Starting from rest, how fast is the crate moving after 4 seconds?
What is 10.2 m/s?
A pilot of mass 70 kg flies a plane in a vertical loop of radius 200 m at a constant speed of 50 m/s. This is the apparent weight (normal force from the seat) of the pilot at the bottom of the loop.
What is 1561 N?
A 2 kg block slides down a frictionless track from rest at a height of 10 m. At the bottom, it compresses a horizontal spring with a spring constant of 400 N/m. What is the maximum spring compression?
What is 0.99 m?
A 60 kg student runs up a flight of stairs rising 5 m vertically in 4 s. This is their average power output.
A 3 kg cart moving at 4 m/s collides head-on and sticks to a stationary 2 kg cart. This is the velocity of the combined carts immediately after the collision.
What is 2.4 m/s?