Forces and Energy

Question 0

Power

• power=..?
• unit of power is watts (W) which is equal to 1 J/s
• power equation?

Answer 0

• power is the rate at which energy is transferred
Power (W)= energy transferred (J)
————————–
Time taken (seconds)

Question 1

Energy and work

Energy transferred= work done
• Work is done on an object when…?
• Work done(Joules) equation??

Work against friction=??

Answer 1

• when…. A force makes the object move
• work done(J)= force (N) x distance moved in the direction of the force(m)

Work done to overcome friction is transferred as heat energy (from the rubbing if the objects) into the surroundings

Question 2

Gravitational pot energy ( Ep )

Increases when?
Decreases when?
•Gains when object is lifted up because?
•Change of grav pot equation?

Answer 2

⬆️ when object moves up
⬇️ when object moves down

Gains when objects lifted because work is done on it to overcome the gravitational force

Change of grav pot= its weight x it’s change in height

Question 3

Kinetic energy

• Depends on an object’s…?
• equation?
• elastic pot energy is..?

Answer 3

Depends in mass and speed

Kinetic energy= 1/2 x mass x speed^2

Elastic pot energy is the energy stored in an elastic object when work is done on the object