Physics Chapter on Impulse and Momentum

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Questions and Answers

Which of the following is consistent with the SI units for impulse?

N s

kg m/s

Both A and B (correct)

None of the above

If a small particle is undergoing erratic motion with no external force acting on it, the direction of the particle's momentum at every point in its motion must always be:

the same as the direction of its net force.

the same as the direction of its velocity. (correct)

the same as the direction of its acceleration.

the same as the direction of its kinetic energy.

A mass 2 m has a velocity v before it strikes a mass 3m at rest. The masses stick together and move off with what velocity?

3v/5

2v/5 (correct)

v/5

5v/2

In this experiment, how can the speed of the disks be ascertained from the burning marks upon the paper?

Measure the distance between any given 2 marks, and divide by spark time. Signup and view all the answers

If the average measured distance between marks generated by a disk (disk A) is greater before a collision with another disk, what can one conclude?

The collision resulted in a deceleration for Disk A. Signup and view all the answers

Two disks (A & B) of equal mass are propelled at equal velocities (V) towards one collision. If they meet in an inelastic collision, what should be the result?

The two disks come to a complete halt at their point of impact. Signup and view all the answers

If disk B has a mass of 10 M and disk A is propelled with velocity V and is halted after an elastic collision with disk B, what will disk B's final kinetic energy be, assuming disk A transfers all the energy to disk B?

1/2 MV^2 Signup and view all the answers

What will be the maximum height of projectile 1's path?

31 m Signup and view all the answers

Approximately how long will it take projectile 2 to travel from its initial launching position to the position in which it lands?

10 sec Signup and view all the answers

Which of the following best explains why projectile 1 travels further in the horizontal direction than projectile 2?

Projectile 1 is launched at a smaller angle to the horizontal. Signup and view all the answers

Which of the following magnitudes represents the vertical velocity of both projectiles?

√(Vi^2 - 2gy) Signup and view all the answers

Which of the following extremes do the projectiles reach when at the highest point of their path?

minimum vertical velocity Signup and view all the answers

An assembly is composed of a 3 kg object attached to a 6 kg object by a weightless rod measuring 6 m in length. How far from the 3 kg object is the center of gravity of the assembly?

4 m Signup and view all the answers

A body is in translational equilibrium if it is:

either at rest or moving with constant velocity. Signup and view all the answers

Which of the following is a proper representation of the relation between torque (τ), length, mass, and time?

τ = [M][L]^2/[T]^2 Signup and view all the answers

In a freak accident, an explosion causes an F-16 jet to divide in half into two equal parts while in flight. At what speed will part B be traveling subsequent to the explosion?

720 km/hr Signup and view all the answers

A clown, standing motionless on a frictionless surface, throws a ball away from herself. If the ball weighs 5 kg, and she throws it at the speed of 3 m/s, how fast will the clown be moving afterward?

0.3 m/s Signup and view all the answers

Which of the following is conserved in an elastic collision?

I. and II. only Signup and view all the answers

Three children of masses 20 kg, 40 kg, and 60 kg want to balance themselves on a 8-meter long seesaw, pivoted at its center. Where must the 20 kg child sit?

3 m from the right end Signup and view all the answers

Study Notes

Impulse and Momentum

Impulse is measured in N·s or kg·m/s, indicating it can be expressed in both force-time and mass-velocity.
Momentum direction matches the direction of velocity; in the absence of external forces, a particle's momentum remains constant.

Inelastic Collisions

In an inelastic collision involving masses of 2m and 3m, the final velocity of the combined masses is calculated as (2v/5).
For two equal-mass disks colliding inelastically with zero initial momentum, they come to a complete stop after impact.

Elastic Collisions

In elastic collisions, momentum and kinetic energy are conserved. The final velocity of disks of different masses must be calculated using conservation laws.
When a disk with mass M collides with a mass 2M disk elastically, the final velocities can be derived using equations for conservation of momentum and kinetic energy.

Projectile Motion

Projectile motion can be split into vertical and horizontal components, simplifying analysis.
Vertical motion is influenced solely by gravity, while horizontal motion retains constant velocity.

Maximum Height and Flight Time

The maximum height for a projectile is determined by its vertical launch velocity and acceleration due to gravity.
The total time a projectile spends in the air can be calculated based on its initial vertical velocity, requiring doubling the time to rise to the maximum height for total flight time.

Horizontal Motion in Projectiles

Projectiles with smaller launch angles achieve greater horizontal distances due to higher horizontal speeds, as horizontal velocity is a function of the cosine of the launch angle.

Center of Gravity

The center of gravity of a composite system is determined using the moments around a pivot point, ensuring rotational equilibrium is maintained.

Equilibrium and Torque

A body in translational equilibrium is either stationary or moving at constant velocity, indicating no net force.
Torque is related to mass, length, and time, with the correct dimensional formula being τ = [M][L]²/[T]².

Conservation of Momentum

In isolated systems, momentum is conserved; for example, if halves of a jet collide, the speed of the moving half after explosion can be calculated based on total momentum before and after.

Seesaw Balancing

The problem of balancing masses on a seesaw involves calculating distances from the pivot using the principle of moments, ensuring that torques are equal for rotational equilibrium.

Summary of Conservation Laws

During elastic collisions, both momentum and kinetic energy are conserved; however, inelastic collisions only conserve momentum.
The analysis of momentum is critical in various collision types and helps predict outcomes in mechanical systems.

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Description

Explore key concepts of impulse, momentum, and collisions in this quiz. Test your understanding of inelastic and elastic collisions, and dive into the details of projectile motion. Perfect for reinforcing your knowledge of fundamental physics principles.