Linear Momentum and Force
What is the formula for linear momentum?
p = mv (momentum = mass × velocity).
What is the formula for impulse?
Impulse = Force × Time (J = FΔt).
State the law of conservation of momentum.
The total momentum of a closed system remains constant if no external forces act on it.
What is an elastic collision?
A collision in which kinetic energy is conserved.
What is an inelastic collision?
A collision in which kinetic energy is not conserved, but momentum is.
What are the units of linear momentum?
Kilogram meters per second (kg·m/s).
How is impulse related to momentum?
Impulse is equal to the change in momentum (J = Δp).
In an isolated system, what happens to the total momentum before and after a collision?
It remains the same.
In an elastic collision, what quantities are conserved?
Both momentum and kinetic energy.
What happens to kinetic energy in a perfectly inelastic collision?
It is converted into other forms of energy like heat or deformation energy.
How does Newton’s second law relate force to momentum?
F = dp/dt (force equals the rate of change of momentum).
What are the units of impulse?
Newton seconds (N·s) or kg·m/s.
How does conservation of momentum apply in two-dimensional collisions?
The total momentum is conserved in both the x and y directions.
Give an example of an elastic collision.
Collisions between billiard balls.
What is a common characteristic of inelastic collisions?
The objects stick together after collision.
What is the momentum of a 3 kg object moving at 4 m/s?
12 kg·m/s.
What happens to an object’s momentum if an impulse is applied to it?
The object’s momentum changes.
If two objects collide and stick together, what type of collision is it?
Perfectly inelastic collision.
Two objects collide elastically. If one is initially at rest, what happens to their velocities?
Their velocities exchange if they have equal mass.
During a car crash, why is some kinetic energy lost?
It is converted into sound, heat, and deformation energy.
If the momentum of a system is conserved, what does this imply about the net external force acting on it?
The net external force is zero.
If a force of 10 N is applied for 2 seconds, what is the impulse?
20 N·s.
A 2 kg object moving at 3 m/s collides with a 4 kg object at rest. What is the final velocity if they stick together?
1 m/s.
If a 1 kg ball moving at 4 m/s collides elastically with a stationary 2 kg ball, and the velocity for the 1 kg ball is -2 m/s after the collision, what is the velocity of the 2 kg ball?
The 2 kg ball moves at 3.0 m/s.
Two cars, one of mass 1500 kg moving at 20 m/s and another of mass 1000 kg moving at 10 m/s, collide inelastically. What is their combined velocity after collision?
16 m/s.