Mechanics and Materials Y2

Question 1

Define moment

Answer 1

Force x perpendicular distance between line of action of force and pivot

Question 2

How would you find the work done to stretch a string?

Answer 2

W=1/2 x F x L

Question 3

What is the purpose of the steel core in overhead cables?

Answer 3

To increase mechanical strength of the cables

Question 4

Why is using a rope with a higher stiffness in a bungee rope a safety concern?

Answer 4

Same KE when rope begins to stretch but jumper stops in shorter distance and increases force on jumper

Question 5

What is GPE lost not transferred to?

Answer 5

Kinetic energy

Question 6

What is Newton’s first law?

Answer 6

Motion of an object will be in a straight line at a constant speed if no resultant force acts on it

Question 7

What is Newton’s second law?

Answer 7

F=ma

Question 8

What is Newton’s third law?

Answer 8

For every reaction there is an equal and opposite reaction

Question 9

State the principal of moments

Answer 9

The sum of clockwise moment equals the sum of anti-clockwise moments for a system in equilibrium

Question 10

What is the area under a velocity time graph equal to?

Answer 10

Displacement

Question 11

Discuss energy transfers which take place when a vehicle is decelerated in a gravel ‘escape’ lane

Answer 11

Kinetic energy of moving vehicle transferred to thermal energy due to friction between tyres and ground causing ground to heat up, and to kinetic energy as gravel pushed aside

Question 12

What is often used in calculations where a moving object increases in height up to a point?

Answer 12

1/2mv^2 = meh

Question 13

Is the change in momentum of an object greater or smaller if it rebounds backwards in a collision?

Answer 13

Greater as change in momentum equals mv - mu