P4 - Momentum Flashcards
What causes acceleration?
If the cars engine exerts a bigger driving force, forwards then if a cost engine exerts a bigger driving force, forwards, than the drag counterforce, the car will accelerate. This means that the resultant force will be in the forward direction, the larger this force is, the greater the acceleration. If the driving force was less than the drag, the car was slow down.
How does acceleration work in rockets?
A rocket taking off accelerates away from the ground, so the upward force, the thrust, must be greater than the downward forces slowing it down. In this case there are two downward forces – gravity and drag. The drag is from friction between the rocket and the air. If the thrust stopped, for example the rocket work to run out of fuel, then the downward forces would be greater than the upward forces and the rocket would slow down until it stopped and then accelerate downward.
What is momentum?
Momentum is mainly about how hard it would be to stop a moving object. The heavier an object is, and the faster it is moving, the harder it is to stop. This means that the object has a greater momentum. Momentum is a vector quality – it has a size and direction like velocity.
What is the equation for momentum?
Momentum (kg m/s) = mass (kg) x velocity (m/s)
What is the nature of the momentum if the object that is moving stays at a constant velocity?
The momentum will be constant.
What will happen to the momentum if the resultant force on an object is not zero?
The momentum will change in the direction of the force.
