W6 - Work, Power & Energy

Question 1

How is Work calculated?

Answer 1

Force x displacement

Question 2

What is mechanical work equal to?

Answer 2

The product of the force applied to object

AND

The displacement of the object while the force is being applied.

Question 3

How is total system work calculated?

Answer 3

Sum of forces x displacement

Question 4

When does positive work occur?

Answer 4

When direction of displacement = direction of force of interest

Question 5

How does negative work occur?

Answer 5

When displacement is in the OPPOSITE direction from the force of interest

Question 6

What type of contraction is linked with negative work?

Answer 6

Eccentric

Question 7

What doesn’t work done consider?

Answer 7

The time over which the force was applied

Question 8

Define power

Answer 8

Rate at which work is performed

Question 9

How is power calculated

Answer 9

Work / time

OR

Force x velocity

Question 10

Units for power

Answer 10

Watts (W)

Question 11

Defne mechanical energy

Answer 11

Capacity of a system to do work

Question 12

In what other way can work be defined?

Answer 12

Change in energy

Question 13

What types of energy can mechanical energy be?

Answer 13

Kinetic

Potential

Question 14

What can potential energy be broken down into?

Answer 14

Gravitational energy

Strain (elastic) energy

Question 15

How can KE be calculated?

Answer 15

1/2 x mass x velocity^2

Question 16

How can gravitational potential energy be calculated?

Answer 16

mass x gravity x height

Question 17

Define gravitational potential energy

Answer 17

Energy an object possess due to its position in a gravitational field.

Question 18

Define strain energy

Answer 18

An object deformed by force may store PE.

Influenced by object stiffness (k)

Question 19

How is strain energy calculated

Answer 19

1/2 x stiffness x X^2

X = Amount of deformation that occurs

Question 20

How is total mechanical energy calculated?

Answer 20

KE + PE + SE