A subatomic particle scatters straight backward from a target particle. In experiments seeking evidence for quarks, electrons were observed to occasionally scatter straight backward from a proton.
Section summary
The conservation of momentum principle is written
or
is the initial total momentum and
is the total momentum some time later.
An isolated system is defined to be one for which the net external force is zero
During projectile motion and where air resistance is negligible, momentum is conserved in the horizontal direction because horizontal forces are zero.
Conservation of momentum applies only when the net external force is zero.
The conservation of momentum principle is valid when considering systems of particles.
Conceptual questions
Professional Application
If you dive into water, you reach greater depths than if you do a belly flop. Explain this difference in depth using the concept of conservation of energy. Explain this difference in depth using what you have learned in this chapter.
Under what circumstances is momentum conserved?
Can momentum be conserved for a system if there are external forces acting on the system? If so, under what conditions? If not, why not?
Momentum for a system can be conserved in one direction while not being conserved in another. What is the angle between the directions? Give an example.
Professional Application
Explain in terms of momentum and Newton’s laws how a car’s air resistance is due in part to the fact that it pushes air in its direction of motion.
Can objects in a system have momentum while the momentum of the system is zero? Explain your answer.
Must the total energy of a system be conserved whenever its momentum is conserved? Explain why or why not.
Problems&Exercises
Professional Application
Train cars are coupled together by being bumped into one another. Suppose two loaded train cars are moving toward one another, the first having a mass of 150,000 kg and a velocity of 0.300 m/s, and the second having a mass of 110,000 kg and a velocity of
. (The minus indicates direction of motion.) What is their final velocity?
0.122 m/s
Suppose a clay model of a koala bear has a mass of 0.200 kg and slides on ice at a speed of 0.750 m/s. It runs into another clay model, which is initially motionless and has a mass of 0.350 kg. Both being soft clay, they naturally stick together. What is their final velocity?
Professional Application
Consider the following question:
A car moving at 10 m/s crashes into a tree and stops in 0.26 s. Calculate the force the seatbelt exerts on a passenger in the car to bring him to a halt. The mass of the passenger is 70 kg. Would the answer to this question be different if the car with the 70-kg passenger had collided with a car that has a mass equal to and is traveling in the opposite direction and at the same speed? Explain your answer.
opposite to the original direction of the car’s motion. In the second case, both cars would come to a complete stop because the total momentum of the two-car system is zero before the collision so it must be zero after the collision. However, if the two cars take longer than 0.26 s to come to a stop upon colliding, then the force exerted on the passenger would be less than
.
What is the velocity of a 900-kg car initially moving at 30.0 m/s, just after it hits a 150-kg deer initially running at 12.0 m/s in the same direction? Assume the deer remains on the car.
A 1.80-kg falcon catches a 0.650-kg dove from behind in midair. What is their velocity after impact if the falcon’s velocity is initially 28.0 m/s and the dove’s velocity is 7.00 m/s in the same direction?
22.4 m/s in the same direction as the original motion
the study of living organisms and their interactions with one another and their environment.
Wine
discuss the biological phenomenon and provide pieces of evidence to show that it was responsible for the formation of eukaryotic organelles in an essay form
advantage of electronic microscope is easily and clearly while disadvantage is dangerous because its electronic. advantage of light microscope is savely and naturally by sun while disadvantage is not easily,means its not sharp and not clear
Abdullahi
cell theory state that every organisms composed of one or more cell,cell is the basic unit of life
Abdullahi
is like gone fail us
DENG
cells is the basic structure and functions of all living things
A scanning electron microscope (SEM) is ideal for situations requiring high-resolution imaging of surfaces. It is commonly used in materials science, biology, and geology to examine the topography and composition of samples at a nanoscale level. SEM is particularly useful for studying fine details,
