Newtons Second Law
OverviewNewton's second law of motion states that the rate of change of momentum of an object is directly proportional to the force applied, and occurs in the direction of the force; where momentum is the product of the mass of the object and its velocity. Therefore a small force is required to propel a small bottle rocket through the air, yet a proportionately much larger amount of force will be required to accelerate a full size rocket. In both cases, in the absence of an external unbalanced force, the force applied to the rocket will be proportional to its rate of change of momentum.
DescriptionNewton's second law defines the relationship between
Example - Car and Trailer
- Determine the acceleration of the system.
- Given that the reistances of the car and trailer are proportional to their masses. Determine the tension in the tow bar
- The driver sees an accident ahead and applies the brakes causing the car to decelerate at . Determine the braking force applied and the force acting in the tow bar.
<h4>Tow bar tension</h4>
As the resistance to motion of the car and trailer are proportional to the masses, then
- The Resistance of the car is
- The Resistance of the traier is
<h4>The car now slows down</h4>
We are told that the car now decelerates at i.e. its has a negative acceleration.
- Acceleration .
- Tension in tow bar is 520N.
- Breaking Force is 2400N. Tension in tow bar is 480N.
Last Modified: 10 Jan 12 @ 17:28 Page Rendered: 2022-03-14 15:55:05