force, work done and energy

Question 1

what is energy?
-si unit?

Answer 1

joules (J)

Question 2

principle of conservation of energy

Answer 2

energy cannot be created or destroyed, but can only be transferred from one object to another, or converted from one form to another

Question 3

what is a force?
-si unit?
-how can it be measured?

Answer 3

push and pull
newton (N)
can be measured with a spring balance

Question 4

pressure formulae
-pressure si unit

** however, if qns asks about n/cm2, just leave ans as N/cm2 as Pa only applies to N/m2!

Answer 4

pascal (Pa)
pressure = force (newton) / area (m2)
pressure is larger when surface area is smaller

Question 5

what is work done

Answer 5

-force applied to an object, causing it to move in the direction of the applied force. Work is done on the object
-energy is transferred (or converted to from on form to another) when work is done

Question 6

For what to be done, what must you have?

Answer 6

~force acting on object
~object must move
~movement of object in the direction of the force

Question 7

work done formula

Answer 7

work done= distance moved by the object * force
joule(J)

Question 8

weight

Answer 8

weight= mass * gravitational field strength

Newton(N)

Question 9

effects of force
-resultant/net force
-balanced, unbalanced forces

Answer 9

if forces are balanced, the resultant force on the object is 0. state of object will remain the same.

balanced: if object at rest, continue staying at rest. but if object is moving, it will continue moving forward in the same direction with constant speed.

unbalanced:
speed will change and/or direction will change