Work - Forces and Energy Changes

Question 1

What is the conservation of energy principle?

Answer 1

Energy. an be transferred usefully, stored or dissipated, but can’t be created or destroyed.

(E.g if a system changes, energy is moved between stores and never disappears.)

Question 2

What is work done mean the same as?

Answer 2

Energy transferred.

So energy is transferred mechanically when a force moves an object.

Question 3

What is power the rate of?

Answer 3

Energy transferred.

Just means that power is how fast energy is transferred or work done.

Question 4

What is power measured in?

Answer 4

Watts.

Question 5

What is the resultant force?

Answer 5

The overall force on a point or object.

Question 6

Fill the gap ;
When a ___ moves an object through a ___, energy is ________ and work _______ on the object.

Answer 6

1. Force
2. distance
3. transferred
4. is done.

Question 7

What is the spring experiment steps when researching link between force and extension?

Answer 7

1) Set up apparatus (weighted stand, ruler clamped to it, connected to a spring with a hanging weight.)

2) measure mass of each weight.

3)calculate its weight (force applied)

4) measure original length of spring.

5) add a mass to the spring and allow it to come to rest.

6) record the force and measure new length of spring, find extension.

7) repeat, plot a graph to find limit of proportionality. (when line starts to curve)

Question 8

what is braking distance affected by?

Answer 8

Speed

Weather

Road surface

Condition of tires

How good brakes are.

Question 9

What does braking rely on?

Answer 9

friction between brakes and wheels.

1) When the brake pedal is pushed, brake pads are pressed onto wheels.
2) This causes friction, causing work to be done.
3) When work is done, energy is transferred.
3) Energy is transferred from the kinetic energy store of vehicle to thermal energy store of brakes, which increases in temperature.
4) To stop a vehicle. the brakes must transfer all of energy from kinetic store.