Forces Part 2

Question 1

Gravity

Answer 1

All matter has a GF, and attracts all other matter. The larger the mass, the stronger the field, the greater the attraction

Question 2

Weight

Answer 2

Force exerted on a mass by the GF, in newtons
Measure by a force meter, measuring scales measure the force u exert and then x 10 - mass
Considered to act on the objects centre of mass’

Question 3

Work done

Answer 3

When a force cause an object to move through a distance work is done on the object. So a force does work on the object when the force cause a displacement if the object. Wd = Fxd 1 joule of work is done when a force of 1 newton causes displacement on one meter

Work done against the frictional forces acting in an object causes a rise in temperature

Question 4

Elastic deformation

Answer 4

The object returns to its normal shape when load is removed. Elastic band.

Question 5

Plastic deformation

Answer 5

Doesn’t return to its og shape when loads removed. A spring when pulled too far.

Question 6

Hookes law

Answer 6

Extension of an elastic object such as spring is directly proportional to force applied, provided that the limit of proportionality is not exceeded. F = kx

Question 7

Linear line for a force/extensfion

Answer 7

Elastic region which follows hooked law. Gradient = k

Question 8

Non linear lime

Answer 8

Plastic behavior not following hookes law if shallow. Lots of extension for not a lot of force, easy to stretch. If graphs is linear then material is so brittle hat snaps not stretched once elastic ,limit is exceeded

Question 9

What happens when a force stretches/compresses a string

Answer 9

Works is done, the elastic potential energy is stored in the spring. Provided it does not inelastically perform. Wd = EPE stored

Question 10

Distance

Answer 10

How far an object moves. Does not involve direction . Scalar quantity

Question 11

Displacement

Answer 11

Includes both the distance an object moves, measured in a straight line from the start point to the finish point and the direction of the straight line. Vector

Question 12

Speed and velocity

Answer 12

Speed - doesn’t involve direction scalar
Velocity - speed in a given direction vector

Question 13

Speed when moving

Answer 13

Rarely constant. When people walk or travel in car speed is constantly changing. Walking - 1.5ms
Run-3ms
Cycle - 6ms

Question 14

Average speed from non uniform

Answer 14

Average speed = total distance/total time

Question 15

Motion in circles

Answer 15

Circular motion - object is constantly changing direction, therefore the velocity, vector - depends on the movement and direction is constantly changing. A change in v is acceleration so even if object not speeding up, it’s accelerating