Motion

Question 1

Displacement time graph - area under, gradient

Answer 1

gradient = velocity

area under = sustained displacement

Question 2

Velocity time graph - area under, gradient

Answer 2

gradient - acceleration
area under - displacement

Question 3

distance time graph - area under , gradient

Answer 3

gradient - speed
area under - nothing

Question 4

acceleration time graph

Answer 4

area under - velocity
gradient - change in acceleration

Question 5

What is the centre of gravity and centre of mass -

Answer 5

the point on an object where the entire weight of the object can be thought to be acting through

Question 6

How to measure centre of gravity

Answer 6

Suspend plumb bob from string and wait till it is vertical

suspend object and draw a line along the plumb line

repeat this at another orientation - the point of intersection is the COG

Question 7

Drag is proportional to

Answer 7

speed squared

Question 8

What is terminal velocity

Answer 8

The point in time in which the weight of an object and the drag are equal and opposite, resulting in 0 resultant force and constant velocity

Question 9

Pully system to investigate terminal velocity

Answer 9

Attach a light polystyrene ball to a pulley by a string to a ball bearing.
Drop ball bearing in liquid
The motion of the polystyrene ball Is identical to the motion of the ball bearing, so its motion can be measured with a motion sensor

Question 10

What is moment of a force

Answer 10

Its the turning effect of a force from a central point or axis
Moment = force x perpendicular distance from line of force to fulcrum

Question 11

what are couples and torques

Answer 11

a couple is a pair of forces that are equal in magnitude, but opposite in directions
they are parallel and act along different lines

Torque is the moment of a couple
torque = force x distance between forces