Forces Flashcards
What two things effect the size of the air resistance?
Surface area and velocity
What do balanced forces do?
Stationary
Constant speed
What is the effect of unbalanced forces?
Change speed
Change velocity
What two things effect weight and what is weight?
Mass and gravity
The effect of gravity on mass
What are the two types of deformation?
Elastic and Inelastic
What goes on the axis when drawing a force by extension graph?
Extension on the x axis
Force on the y axis
What is hooke’s law?
The force is proportional to the extension
What is the limit of proportionality?
When the force applied stops being proportional to the extension
What factors effect if something will sink or float?
Density of the liquid
Gravitational field strength
What forces does an object experience when in water?
Forces from all directions, however because the bottom is deeper than the top, the bottom pressure is greater the pressure at the top, causing the water at the bottom to push up, known as upthrust
What happens to the atmospheric pressure the further away you go from the earth’s surface?
It decreases because there would be less air particles so there would be less collisions as there’s less air so a lower pressure. There would also be less air particles above it so it would have a lower weight of air above it which contributes to pressure
Explain the forces acting on a person when they jump out a plane?
When someone jumps out an aeroplane, gravity would be pulling the person down (weight). The weight of the person would result in the person accelerating towards the ground. As the person accelerates they collide with more air particles which results in an increasing opposite force until the force of friction from air resistance and the weight of the person are equal, this is terminal velocity. The person stops accelerating and has a constant speed. If the person opens a parachute they have a larger surface area so more air particles can collide with the surface area. Now the resultant force would be upwards so the person starts to decelerate and the person starts to slow down, as the person slows down the friction from air resistance becomes smaller and smaller until the force of friction is the same as the weight. The resultant force is now zero and there is a new lower terminal velocity.
