Exam 8: Momentum and Collisions

A rocket moving in outer space maintains a constant acceleration (magnitude = 20 m/s²)while ejecting fuel at a speed of 15 km/s relative to the rocket.If the initial mass of the rocket is 3 000 kg,what is the magnitude of the thrust after 800 kg of fuel have been consumed?

A 3.0-kg mass sliding on a frictionless surface has a velocity of 5.0 m/s east when it undergoes a one-dimensional inelastic collision with a 2.0-kg mass that has an initial velocity of 2.0 m/s west.After the collision the 3.0-kg mass has a velocity of 1.0 m/s east.How much kinetic energy does the two-mass system lose during the collision?

Car A rear ends Car B,which has twice the mass of A,on an icy road at a speed low enough so that the collision is essentially elastic.Car B is stopped at a light when it is struck.Car A has mass m and speed v before the collision.After the collision

A 5.0-g particle moving 60 m/s collides with a 2.0-g particle initially at rest.After the collision each of the particles has a velocity that is directed 30 $\degree$ from the original direction of motion of the 5.0-g particle.What is the speed of the 2.0-g particle after the collision?

The speed of a 2.0-kg object changes from 30 m/s to 40 m/s during a 5.0-s time interval.During this same time interval,the velocity of the object changes its direction by 90 $\degree$ .What is the magnitude of the average total force acting on the object during this time interval?

A 1.0-kg object moving 9.0 m/s collides with a 2.0-kg object moving 6.0 m/s in a direction that is perpendicular to the initial direction of motion of the 1.0-kg object.The two masses remain together after the collision,and this composite object then collides with and sticks to a 3.0-kg object.After these collisions,the final composite (6.0-kg)object remains at rest.What was the speed of the 3.0-kg object before the collisions?

Three particles are placed in the xy plane.A 30-g particle is located at (3,4)m,and a 40-g particle is located at (-2,-2)m.Where must a 20-g particle be placed so that the center of mass of the three-particle system is at the origin?

At the instant a 2.0-kg particle has a velocity of 4.0 m/s in the positive x direction,a 3.0-kg particle has a velocity of 5.0 m/s in the positive y direction.What is the speed of the center of mass of the two-particle system?

A uniform thin wire has a length $L = \pi R$ and is bent into a semicircular arc of radius R.If the wire starts at (x,y)= (R,0)and curves counterclockwise to (x,y)= (-R,0),what is the y coordinate of its center of mass?

A 3.0-kg object moving 8.0 m/s in the positive x direction has a one-dimensional elastic collision with an object (mass = M)initially at rest.After the collision the object of unknown mass has a velocity of 6.0 m/s in the positive x direction.What is M?

A 6.0-kg object moving 2.0 m/s in the positive x direction has a one-dimensional elastic collision with a 4.0-kg object moving 3.0 m/s in the opposite direction.What is the total kinetic energy of the two-mass system after the collision?

A 3.0-kg mass sliding on a frictionless surface explodes into three 1.0-kg masses.After the explosion the velocities of the three masses are: (1)9.0 m/s,north;(2)4.0 m/s,30 $\degree$ south of west;and (3)4.0 m/s,30 $\degree$ south of east.What was the magnitude of the original velocity of the 3.0-kg mass?

A 4.0-kg particle is moving horizontally with a speed of 5.0 m/s when it strikes a vertical wall.The particle rebounds with a speed of 3.0 m/s.What is the magnitude of the impulse delivered to the particle?

A 6.0-kg object moving 5.0 m/s collides with and sticks to a 2.0-kg object.After the collision the composite object is moving 2.0 m/s in a direction opposite to the initial direction of motion of the 6.0-kg object.Determine the speed of the 2.0-kg object before the collision.

Exhibit 9-1 Use this exhibit to answer the following question. Two birds of prey hurtling after the same mouse collide in mid-air and grab each other with their talons.Each 250-g bird is flying at 30 m/s at a 60 $\degree$ angle to the ground. -Refer to Exhibit 9-1.What is the magnitude of their total momentum,in $\frac { \mathrm { kg } \cdot \mathrm { m } } { \mathrm { s } }$ ,immediately after the collision?

A pendulum consists of a 2.0-kg block hanging on a 1.5-m length string.A 10-g bullet moving with a horizontal velocity of 900 m/s strikes,passes through,and emerges from the block (initially at rest)with a horizontal velocity of 300 m/s.To what maximum height above its initial position will the block swing?

A 2.0-kg object moving with a velocity of 5.0 m/s in the positive x direction strikes and sticks to a 3.0-kg object moving with a speed of 2.0 m/s in the same direction.How much kinetic energy is lost in this collision?

A rocket engine consumes 450 kg of fuel per minute.If the exhaust speed of the ejected fuel is 5.2 km/s,what is the thrust of the rocket?

An 8.0-kg object moving 4.0 m/s in the positive x direction has a one-dimensional collision with a 2.0-kg object moving 3.0 m/s in the opposite direction.The final velocity of the 8.0-kg object is 2.0 m/s in the positive x direction.What is the total kinetic energy of the two-mass system after the collision?

A 500-g firework explodes into two pieces of equal mass at an instant when it is traveling straight up at 10 m/s.If one half shoots off horizontally to the left at 20 m/s,what is the velocity,in m/s,of the other half immediately after the explosion? (The x axis is directed right;the y axis up. )