IMPULSE

CONTENTS

• Big Idea
• Demo
• Word Problems
• Real Life Applications

1. BIG

IMPULSE is a SUDDEN CHANGE OF SPEED in an
OBJECT'S MOMENTUM. This concept was
DERIVED FROM NEWTON'S 2ND LAW which
could be summarized into F=M*A. How does
It derive from that? ACCELERATION can be DEFINED
also as VELOCITY/TIME, so the equation now is
F=m*v/t. When the equation is multiplied by
the factor time the equation will now be
F*t=m*v. We now see the connection of
two, F*t which is the equation which is for impulse…

When the equation is multiplied by
the factor time the equation will now be
F*t=m*v. We now see the connection of
two, F*t which is the equation which is for impulse
and m*v which says the change of momentum.In a collision, an object experiences a force for a specific amount of time that results in a change in momentum. The result of the force acting for the given amount of time is that the object's mass either speeds up or slows down (or changes direction). The impulse experienced by the object equals the change in momentum of the object. In equation form, F • t = m • Δ v.

WORD
PROBLEMS

1. A 0.50-kg cart 1 is pulled with a 1.0-N force for 1 second; another 0.50 kg cart 2 is pulled with a 2.0 N-force for 0.50 seconds.

ANSWER THE FF.

• Which cart (#1 or #2) has the greatest acceleration? Explain.
• Which cart (#1 or #2) has the greatest impulse? Explain.
• Which cart (#1 or #2) has the greatest change in momentum? Explain.

Cart #2 has the greatest acceleration. Recall that acceleration depends on force and mass. They each have the same mass, yet cart #2 has the greater force.

The impulse is the same for each cart. Impulse is force*time and can be calculated to be 1.0 N*s for each cart.

The momentum change is the same for each cart. Momentum change equals the impulse; if each cart has the same impulse, then it would follow that they have the same momentum change.

TRY THIS:
A hockey player applies an average force of 80.0 N to a 0.25 kg hockey puck for a time of 0.10 seconds.

AnsweR This

• Determine the impulse experienced by the hockey puck.
• Find the acceleration

Impulse = F*t = 80 N * 0.1 s
Impulse = 8 N*s
Acceleration = F/m = 80 N/ 0.25 kg
Acceleration = 0.32 m/s
Note that not all the numbers are necessary for computing the impulse; don't "force" the value of mass into the computation.

REAL LIFE

HERE ARE SOME EXmples of impulse:

1. Basketball

Occasionally when objects collide, they bounce off each other as opposed to sticking to each other and traveling with the same speed after the collision. Bouncing off each other is known as REBOUNDING. Rebounding involves a change in the direction of an object; the before- and after-collision direction is different. Rebounding situations are characterized by a large velocity change and a large momentum change.

2. MOUNTAIN CLIMBING

Nylon ropes are used in the sport of rock-climbing for the same reason. Rock climbers attach themselves to the steep cliffs by means of nylon ropes. If a rock climber should lose her grip on the rock, she will begin to fall. In such a situation, her momentum will ultimately be halted by means of the rope, thus preventing a disastrous fall to the ground below. The ropes are made of nylon or similar material because of its ability to stretch.

If the rope is capable of stretching upon being pulled taut by the falling climber's mass, then it will apply a force upon the climber over a longer time period. Extending the time over which the climber's momentum is broken results in reducing the force exerted on the falling climber. For certain, the rock climber can appreciate minimizing the effect of the force through the use of a longer time of impact. Now that's physics in action.

IMPULSE

MATTHEW ROSALIN

Michael Abuan

EMMAN MAGBAnua