1 Forces and movement Flashcards
What is the formula for force?
F = m x a
What are the units used in the formula for force?
(N) = (kg) x (m/s^2)
What is the formula for weight?
W = m x g
What are the units used in the formula for weight?
(N) = (kg) x (N/Kg)
What is the stopping distance of a car?
It is made up of the thinking and the braking distance.
What is thinking distance?
The distance the driver moves while taking time to react to whatever is in front of him.
What affects the thinking distance?
- Reaction time
- If the driver is under the influence.
- Poor visibility (fog)
- Speed
What is braking distance?
The distance travelled by the vehicle after the driver has pressed the breaks.
What affects the braking distance?
- Tires or brakes are in poor condition.
- Road condition.
- The vehicles mass.
What kind of force does an object through the air experience?
Air resistance or drag (A force that opposes its motion).
What does the size of the drag force acting on an object depend on?
Its shape and its speed.
What are kind of relationship do speed and drag force have?
Directly proportional.
What are the two main forces that objects falling through the air experience?
- Weight (pull of gravity on the object).
- The opposing drag force.
When is there drag force?
When the object is moving.
What forces are acting on an object when it is first released into air?
The starting velocity is 0m/s, so this means that there is no drag, but there is a resultant downward-acting force that is the weight force which makes an object accelerate towards earth.
What is happening in this graph?
A’ is when the skydiver reaches terminal velocity at free-fall. However, at point B the skydiver opens their parachute which causes a major and very quick drop in their velocity. Point C’ shows when terminal velocity is reached when the skydivers parachute is open.
