3.3 Forces Flashcards
(15 cards)
What is weight?
the gravitational force acting on an object
What is friction?
acts along the surface in the opposite direction to motion
What is drag?
the resistive force that acts against motion when a body moves through a fluid - reduced by making an object streamlined
What is upthrust?
the upward force exerted on a body in a fluid. equal to the weight of fluid displaced by the object
What is contact force?
when a surface exerts a force at a right angle to the force being applied to it
What is tension?
when a rope is stretched there is a tension pulling inwards to restore its length
How do you calculate the component of weight acting down a slope?
Wsin0
If block held in place by friction then this is force of friction
How do you calculate the component of weight perpendicular to the slope?
Wcos0
What is Newton’s first law?
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction (0 net force) unless acted upon by an unbalanced force
What is Newton’s second law?
F = ma
What is Newton’s third law?
Every force has an equal and opposite reaction force
Define 1 Newton
the force required to accelerate a mass of 1kg through an acceleration of 1ms-2 in the direction of force
1N = 1kgms-2
How do you calculate drag?
D = kv2 where k is a constant for the moving object
Drag depends on:
velocity cross-sectional area how streamlined the object is texture of surface viscosity/temperature/density of medium
What is lift?
an upward force that acts on a wing as it moves forwards through the air
